3870 ta raf alconbury, cambridgeshire

m.hildon

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Explosive Ordnance Threat Assessment in respect of RAF Alconbury For Buro Four 3870TA 19th April 2012

m.hildon

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BACTEC International Limited

37 Riverside, Sir Thomas Longley Road, Rochester, Kent ME2 4DP, UK

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Explosive Ordnance Threat Assessment

in respect of

RAF Alconbury

for

Buro Four

3870TA 19th April 2012

Buro Four RAF Alconbury

Report: 3870TA ii BACTEC International Limited

This document was written by, belongs to and is copyright to BACTEC International Limited. It contains valuable BACTEC proprietary and confidential information which is disclosed only for the purposes of the client’s assessment and evaluation of the project which is the subject of this report. The contents of this document shall not, in whole or in part (i) be used for any other purposes except such assessment and evaluation of the project; (ii) be relied upon in any way by the person other than the client (iii) be disclosed to any member of the client’s organisation who is not required to know such information nor to any third party individual, organisation or government, or (iv) be copied or stored in any retrieval system nor otherwise be reproduced or transmitted in any form by photocopying or any optical, electronic, mechanical or other means, without prior written consent of the Managing Director, BACTEC International Limited, 37 Riverside, Sir Thomas Longley Road, Rochester, Kent, ME2 4DP, United Kingdom to whom all requests should be sent. Accordingly, no responsibility or liability is accepted by BACTEC towards any other person in respect of the use of this document or reliance on the information contained within it, except as may be designated by law for any matter outside the scope of this document.

Distribution

This Report has been produced in compliance with the Construction Industry Research and Information Association guidelines for the preparation of Detailed Risk Assessments in the

management of UXO risks in the construction industry.

Copy No. Format Recipient

1 Print Copy Buro Four

2 PDF Copy Buro Four

3 Print Copy BACTEC International Limited

Date of Issue:

19th April 2012

Copy no.

2

Originator: OTB


Report: 3870TA iii BACTEC International Limited

Glossary of Terms

AAA Anti-Aircraft Artillery

ARP Air-raid Precautions

BDO Bomb Disposal Officer

EOD Explosive Ordnance Disposal (current term for “bomb” disposal)

HE High Explosive

HG Home Guard

IB Incendiary Bomb

kg Kilogram

LCC London County Council

LM Land Mine

LSA Land Service Ammunition (includes grenades, mortars, etc.)

Luftwaffe German Air Force

m bgl Metres Below Ground Level

MoD Ministry of Defence

OB Oil Bomb

PM Parachute Mine

RAF Royal Air Force

SI Site Investigation

SAA Small Arms Ammunition (small calibre cartridges used in rifles & machine guns)

USAAF United States Army Air Force

UXB Unexploded Bomb

UXO Unexploded Ordnance

V-1 “Doodlebug” the first cruise type missile, used against London

from June 1944. Also known as ‘Flying Bomb’.

V-2 The first ballistic missile, used against London from September 1944

WWI First World War (1914 -1918)

WWII Second World War (1939 – 1945)


Report: 3870TA iv BACTEC International Limited

Executive Summary The Site: The site is located just north and east of the villages of Alconbury, Little Stukeley and Great Stukeley in Cambridgeshire. It is mostly bound by agricultural fields however a railway line is present immediately east and the A1 and B1043 border the site to the south-west. The majority of the study area, centred on the approximate National Grid Reference: 521572, 276540, is currently occupied by RAF Alconbury airbase. The site boundary currently includes runways, taxi ways, dispersal pans, numerous hangars, a WWII-era technical site, a post-WWII bomb dump, many other ancillary buildings and also a large agricultural area to the south-east of the airbase perimeter. Proposed Works: A large mixed use development is proposed over the entire site. Note however that many parts of the site will not require intrusive work as they will become open spaces or woodland. No precise details regarding the types and depth of the proposed intrusive works were available during the production of this report. Risk Assessment Methodology: In accordance with CIRIA guidelines this assessment has carried out research, analysed the evidence and considered the risks that the site has been contaminated with unexploded ordnance; that such items remained on site; that they could be encountered during the proposed works and the consequences that could result. Appropriate risk mitigation measures have been proposed. Explosive Ordnance Risk Assessment: BACTEC concludes that there are areas of Low/Medium, Medium/High and High risk at the site of the proposed development. This is based on the following factors:

Allied Unexploded Ordnance Risk

o The site is partially situated within the historic perimeter of RAF Alconbury, a WWII-era/Cold War-era airbase.

Experience has shown that the ‘housekeeping’ at historic RAF/USAAF stations was often poor with unwanted or unused ordnance sometimes buried, burnt, lost or otherwise discarded within or in close proximity to the airfield perimeter. Furthermore, the requirement for a swift post-WWII USAAF exit from England meant that some American military equipment was simply abandoned, poorly disposed of or buried within or close to their bases.

o Previous BACTEC work on several former RAF stations has shown that the former bomb stores and dispersal pans/aircraft armament areas (where aircraft were loaded with weapons), have a higher risk of UXO contamination. As these features were/are located within the study area, the risk of encountering such munitions is elevated. BACTEC also recently exhumed WWII British HE bombs buried outside the perimeter of RAF Oakington, a WWII RAF Bomber Command base.

o 1946 RAF Alconbury site plans show that several defence huts, pyrotechnics stores, armouries and gunnery ranges were positioned around the airfield, away from the bomb dump. The locations of these features will also have a slightly heightened risk of UXO associated with them.

o Home Guard units and possibly regular army units are likely to have carried out guard duties and training within and in close proximity to the base. During such activities small arms ammunition and land service ammunition (grenades, mortars, etc) would have been issued to personnel, increasing the chance of UXO contamination.

o If UXO remains at RAF Alconbury it is more likely to be of WWII-era because the frequency and intensity of operations during this period, coupled with a generally more relaxed attitude towards health and safety meant that items of UXO were more likely to be misplaced or buried. Although RAF/USAF rules and regulations regarding handling and storage of munitions have become increasingly more stringent in the post-WWII period, the possibility cannot be discounted that American UXO from the period 1953 – 1995 could be encountered on site, particularly in the current bomb dump facility, to the north.

German Unexploded Ordnance Risk

o Due to its rural nature, Alconbury was situated in an area of low bombing density throughout WWII. The only viable Luftwaffe targets in the region were several RAF airfields including that which occupied the site. The presence of this facility did locally raise the bombing density however. Records indicate that three small scale air raids were made on the airbase between 1940 and 1941. These attacks resulted in 46 HE bombs recorded on and close to the airfield.

o Levels of access will have been variable across different parts of the site. Generally the main airfield site and communal area to the west would have been regularly frequented during the war. Furthermore, the buildings are likely to have been subject to checks for evidence of UXO, that would have been fairly obvious, following the air raids. During the raids it is considered highly likely that AA defences at the airfield would have engaged the attackers. This coupled with the small number of aircraft involved suggests it is likely that a UXB strike would have been observed.

o The airfield peripheries and the agricultural area to the south-east will have been accessed to a much lesser degree. Therefore it is conceivable that a UXB strike could have gone unobserved and an entry hole would have been easily obscured; note that the entry hole of an SC 50 HE UXB, the most commonly deployed HE bomb, may have been as small as 20cm in diameter and therefore easily obscured by dense crops or soil debris (ploughed field).


Report: 3870TA v BACTEC International Limited

o Immediate post-WWII RAF aerial photography of the site does not exhibit any large scale damage or bomb

craters within the study area. An anecdotal account also describes only minor damage to two aircraft during the three air raids.

For the large part there has not been any significant redevelopment of the airfield since it became a non-operational base in 1995. There has however been some development within the airfield in the post-WWII period and therefore the risk of encountering shallow buried UXO (such as SAA, 1kg German incendiaries, AAA shells and USAAF munitions) in these areas will have been partly mitigated since any such items may have been discovered during excavations. However the risk from deep-buried German HE UXBs will only have been mitigated at the precise locations of and down to the depths of any post-war deep excavations or pile foundations. Note that the risk posed by these munitions is considered to be relatively low. Ploughing and re-working of farmland has been known to exhume shallow buried items of UXO, however purposely buried UXO has also been encountered at depths below that of normal ploughing methods. Therefore the risk of encountering UXO at any depth within the south-eastern part of the study area will not have been fully mitigated. Bomb Penetration Assessment: It has been assessed that a 500kg bomb would have had a maximum bomb penetration depth of up to 12m below WWII ground level. Penetration depth could potentially have been greater if the UXB was larger (though only 4% of German bombs used in WWII over Britain were of that size). Note that UXBs may be found at any depth between just below the WWII ground level and the maximum penetration depth. Risk Mitigation Measures: Due to the large scale and complexity of the RAF Alconbury redevelopment BACTEC suggests that a meeting be held with Buro Four in order to create a bespoke risk mitigation strategy for the site, prior to intrusive works. This is likely to include the following mitigation measures: All Risk Zones o Explosive Ordnance Safety and Awareness Briefings to all personnel conducting intrusive works.

o The provision of Unexploded Ordnance Site Safety Instructions. Medium/High and High Risk Zones only o On greenfield areas only: Non-Intrusive Magnetometer Survey and target investigation ahead of any intrusive

works.

In developed areas, including areas of hard-standing, roads, made ground, buildings, etc a Non-Intrusive Magnetometer Survey is inappropriate due to high levels of background ‘noise’. In these areas the following is recommended:

o Explosive Ordnance Disposal (EOD) Engineer presence on site to support shallow intrusive works. In making this assessment and recommending these risk mitigation measures, the proposed works outlined in the ‘Scope of the Proposed Works’ section were considered. Should the planned works be modified or additional intrusive engineering works be considered, BACTEC should be consulted to see if a re-assessment of the risk or mitigation recommendations is necessary. Risk Map

High Risk Zone

Medium/High Risk Zone

Low/Medium Risk Zone


Report: 3870TA vi BACTEC International Limited

Contents Distribution ........................................................................................................................... ii

Glossary of Terms ................................................................................................................ iii

Executive Summary .............................................................................................................. iv

Contents ............................................................................................................................... vi

Annexes ............................................................................................................................. viii

1. Introduction .................................................................................................................. 1 1.1. Background ........................................................................................................................... 1

2. Construction Industry Duties and Responsibilities ......................................................... 2 2.1. The UK Regulatory Environment .............................................................................................. 2 2.2. The Health and Safety at Work Act, 1974 ................................................................................. 2 2.3. Construction (Design and Management) Regulations 2007 .......................................................... 2 2.4. Other Legislation ................................................................................................................... 2

3. The Role of the Authorities and Commercial Contractors ............................................... 2 3.1. The Authorities ...................................................................................................................... 2 3.2. Commercial Contractors ......................................................................................................... 3

4. This Report .................................................................................................................... 3 4.1. Aims and Objectives ............................................................................................................... 3 4.2. Risk Assessment Methodology ................................................................................................. 3 4.3. Approach .............................................................................................................................. 3 4.4. Sources of Information ........................................................................................................... 3 4.5. Reliability of Historical Records ................................................................................................ 4 4.5.1. General Considerations ........................................................................................................... 4 4.5.2. Bombing Records ................................................................................................................... 4

5. The Site ......................................................................................................................... 4 5.1. Site Location ......................................................................................................................... 4 5.2. Site Description ..................................................................................................................... 4

6. Scope of the Proposed Works ........................................................................................ 4

7. Ground Conditions ......................................................................................................... 5

8. Site History .................................................................................................................... 5 8.1. Mapping ............................................................................................................................... 5 8.2. History of RAF Alconbury ........................................................................................................ 5 8.2.1. RAF Use 1938 - 1942 ............................................................................................................. 5 8.2.2. USAAF WWII Use 1942 - 1945 ................................................................................................ 6 8.2.3. USAF Cold War Use 1953 – Present .......................................................................................... 6

9. The Threat from Allied Military Ordnance ....................................................................... 7 9.1. RAF Station Contamination ..................................................................................................... 7 9.2. General ................................................................................................................................ 7 9.3. Ground Defensive Positions ..................................................................................................... 7 9.3.1. Anti-Aircraft Artillery Gun Emplacements .................................................................................. 7 9.4. Home Guard Training ............................................................................................................. 8 9.5. Ordnance/Explosives Storage and Disposal ............................................................................... 8 9.6. Practice Bombing ................................................................................................................... 8 9.7. Aircraft Weapons Testing ........................................................................................................ 9 9.8. Pipe Mines/Demolition Charges ................................................................................................ 9

10. Threat Posed By Allied Explosive Ordnance ................................................................... 9 10.1. General ................................................................................................................................ 9 10.2. Small Arms Ammunition (SAA) ................................................................................................ 9 10.3. Land Service Ammunition (LSA) .............................................................................................. 9 10.3.1. General ................................................................................................................................ 9


Report: 3870TA vii BACTEC International Limited

10.3.2. Mortars .............................................................................................................................. 10 10.3.3. Grenades ............................................................................................................................ 10 10.4. Miscellaneous ...................................................................................................................... 10 10.5. Anti-Aircraft Artillery Shells ................................................................................................... 10 10.6. Practice Bombs .................................................................................................................... 10 10.6.1. Bomb Characteristics ........................................................................................................... 10 10.6.2. Explosive Content ................................................................................................................ 11 10.6.3. Hazards .............................................................................................................................. 11 10.7. Allied High Explosive and Incendiary Ordnance ........................................................................ 11

11. The Threat from Aerial Bombing .................................................................................. 12 11.1. General Bombing History of Huntingdonshire ........................................................................... 12 11.1.1. First World War ................................................................................................................... 12 11.1.2. Second World War ............................................................................................................... 12 11.2. Aerial Delivered Ordnance in the Second World War ................................................................. 12 11.2.1. Generic Types of WWII German Air-delivered Ordnance ........................................................... 12 11.2.2. German Air-delivered Ordnance Failure Rate ........................................................................... 13 11.2.3. UXB Ground Penetration ....................................................................................................... 13 11.2.3.1. General Considerations ......................................................................................................... 13 11.2.3.2. The “j” Curve Effect ............................................................................................................. 13 11.2.3.3. Second World War Bomb Penetration Studies .......................................................................... 14 11.2.4. Initiation of Unexploded Bombs ............................................................................................. 14 11.3. Bombing of Alconbury .......................................................................................................... 14 11.3.1. Second World War Overview ................................................................................................. 14 11.3.2. Second World War Bombing Statistics .................................................................................... 15 11.3.3. Site Specific Bombing ........................................................................................................... 15 11.3.4. Second World War Era Aerial Photographs .............................................................................. 15 11.3.5. Abandoned Bombs ............................................................................................................... 15 11.3.6. Site Specific Bomb Penetration Considerations ........................................................................ 16 11.4. Deductions .......................................................................................................................... 16 11.4.1. Density of Bombing .............................................................................................................. 16 11.4.2. Frequency of Access ............................................................................................................. 16 11.4.3. Ground Cover ...................................................................................................................... 17 11.4.4. Damage.............................................................................................................................. 17 11.4.5. Bomb Failure Rate ............................................................................................................... 17

12. Ordnance Clearance and Post-WWII Ground Works .................................................... 17 12.1. General .............................................................................................................................. 17 12.1.1. EOD Bomb Disposal and Clearance Tasks ................................................................................ 17 12.2. Post-War Redevelopment ...................................................................................................... 17

13. The Overall Explosive Ordnance Threat Assessment .................................................... 18 13.1. General Considerations ......................................................................................................... 18 13.2. The Risk that the Site was Contaminated with Unexploded Ordnance ......................................... 18 13.3. The Risk that Unexploded Ordnance Remains on Site ............................................................... 19 13.4. The Risk that Ordnance may be Encountered during the Works ................................................. 19 13.5. The Risk that Ordnance may be Initiated ................................................................................ 19 13.6. The Consequences of Encountering or Initiating Ordnance ........................................................ 19 13.7. BACTEC’s Assessment .......................................................................................................... 20

14. Proposed Risk Mitigation Strategy ............................................................................... 21 14.1. General .............................................................................................................................. 21 14.2. Recommended Risk Mitigation Measures ................................................................................. 21

Bibliography ........................................................................................................................ 23


Report: 3870TA viii BACTEC International Limited

Annexes

Annex A Site Location Maps

Annex B Recent Aerial Photograph of the Site

Annex C Proposed Site Plan

Annex D WWII-era RAF Alconbury Site Plan

Annex E 1946 RAF Alconbury Site Plan

Annex F RAF Oakington UXBs Discovery

Annex G Small Arms Ammunition

Annex H Land Service Ammunition

Annex I Miscellaneous Military Contamination

Annex J Anti-Aircraft Artillery

Annex K Allied Air-Delivered Practice Bombs

Annex L Allied Air-Delivered Ordnance

Annex M WWI UK Air-Raids and Naval Bombardments Map

Annex N German Air-Delivered Ordnance

Annex O UXO Press Articles

Annex P Huntingdonshire Bomb Density Map

Annex Q WWII-era RAF Aerial Photography

Annex R Incendiary Bomb Penetration Photograph

Annex S Risk Map


Report: 3870TA 1 BACTEC International Limited

Explosive Ordnance Threat Assessment

In Respect of

RAF Alconbury

1. Introduction

1.1. Background Buro Four has commissioned BACTEC International Limited to conduct an Explosive Ordnance Threat Assessment for the proposed development works at the RAF Alconbury site, Cambridgeshire. Unexploded Ordnance (UXO) presents a significant threat to construction projects in parts of the UK as a result of enemy actions during the two 20th Century world wars and historic British and Allied military activity.

The site comprises RAF/USAF (United States Air Force) Alconbury, a non-operational airbase currently administered by the USAF. On sites formerly used by the military there is the potential for Allied operations to have left a legacy of explosive ordnance contamination. Munitions storage, weapons testing and ground personnel training can all contribute to an explosive ordnance contamination risk; one that is often substantiated through the discovery of unexploded weapons, by the public and the construction industry, at former MoD sites.

A legacy of WWII is buried unexploded (German/Italian) air-dropped bombs or (British) anti-aircraft projectiles, resulting from the failure of a proportion of these weapons to function as designed. It is commonly accepted that the failure rate of these munitions was approximately 10% and, depending on their shape, weight, velocity and ground conditions, many penetrated the ground and came to rest at depth. Intensive efforts were made during and after the war to locate and render safe all UXO but, unsurprisingly, not all were found and dealt with. The UK was also bombed during WWI, though to a much lesser extent, and it is thought that a similar proportion of these weapons also malfunctioned. There have been occasional finds of unexploded WWI bombs in recent years but the risk of encountering them today is generally very low. As a result of generally increased risk awareness amongst professionals involved in ground engineering works and proactive health and safety measures, the threat to life and limb from UXO has been minimised. However even the simple discovery of a suspected device during ongoing works can cause considerable disruption to production and cause unwanted delays and expense. Such risks can be more fully controlled by a better understanding of the site-specific threat and the implementation of appropriate risk mitigation measures.



2. Construction Industry Duties and Responsibilities

2.1. The UK Regulatory Environment There is no specific legislation covering the management and control of the UXO risk in the UK construction industry but issues regarding health and safety are addressed under a number of regulatory instruments, as outlined below. In practice the regulations impose a responsibility on the construction industry to ensure that they discharge their obligations to protect those engaged in ground-intrusive operations (such as archaeology, site investigation, drilling, piling or excavations) from any reasonably foreseeable UXO risk.

2.2. The Health and Safety at Work Act, 1974 The Act places a duty of care on an employer to put in place safe systems of work to address, as far as is reasonably practicable, all risks (to employees and the general public) that are reasonably foreseeable.

2.3. Construction (Design and Management) Regulations 2007 This legislation defines the responsibilities of all parties (primarily the Client, the CDM Co-ordinator, the Designer and the Principal Contractor) involved with works. Although UXO issues are not specifically addressed the regulations effectively place obligations on all these parties to:

o Ensure that any potential UXO risk is properly assessed.

o Put in place appropriate risk mitigation measures if necessary.

o Keep all parties affected by the risk fully informed.

o Prepare a suitably robust emergency response plan.

2.4. Other Legislation Other relevant legislation includes the “Management of Health and Safety at Work Regulations 1999” and “The Corporate Manslaughter and Corporate Homicide Act 2007”.

3. The Role of the Authorities and Commercial Contractors

3.1. The Authorities The Police have the responsibilities for co-ordinating the emergency services in the case of an ordnance-related incident on a construction site. They will make an initial assessment (i.e. is there a risk that the find is ordnance or not?) and if they judge necessary impose a safety cordon and/or evacuation and call the military authorities (JSEODOC - Joint Services Explosive Ordnance Disposal Operations Centre) to arrange for investigation and/or disposal. In the absence of an EOD specialist on site many Police Officers will use the precautionary principle, impose cordon(s)/evacuation and await advice from the JSEODOC. The priority given to the request by JSEODOC will depend on their judgement of the nature of the threat (ordnance, location, people and assets at risk) and the availability of resources. They may respond immediately or as resources are freed up. Depending on the on-site risk assessment the item of ordnance may be removed or demolished (by controlled explosion) in-situ. In the latter case additional cordons and/or evacuations may be necessary. Note that the military authorities will only carry out further investigations or clearances in very high profile or high risk situations. If there are regular ordnance finds on a site the JSEODOC may not treat each occurrence as an emergency and will encourage the construction company to put in place alternative procedures (i.e the appointment of a commercial contractor) to manage the situation and relieve pressure from the JSEODOC.



3.2. Commercial Contractors

In addition to pre-construction site surveys and clearances a commercial contractor is able to provide a reactive service on construction sites. The presence of a qualified EOD Engineer with ordnance recognition skills will avoid unnecessary call-outs to the authorities and the Contractor will be able to arrange for the removal and disposal of low risk ordnance. If high risk ordnance is discovered actions will be co-ordinated with the authorities with the objective of causing the minimum possible disruption to site operations whilst putting immediate, safe and appropriate measures in place.

4. This Report

4.1. Aims and Objectives

The aim of this report is to examine the possibility of encountering any explosive ordnance during the proposed works at the RAF Alconbury site. Risk mitigation measures will be recommended, if deemed necessary, to reduce the threat from explosive ordnance during the envisaged works. The report follows the CIRIA Guidelines.

4.2. Risk Assessment Methodology

The following issues will be addressed in the report:

o The risk that the site was contaminated with unexploded ordnance.

o The risk that unexploded ordnance remains on site.

o The risk that ordnance may be encountered during the proposed works.

o The risk that ordnance may be initiated.

o The consequences of initiating or encountering ordnance.

Risk mitigation measures, appropriate to the assessed level of risk and site conditions, will be recommended if required.

4.3. Approach

In preparing this Explosive Ordnance Threat Assessment Report, BACTEC has considered general and, as far as possible, site specific factors including:

o Evidence of German bombing and delivery of UXBs.

o Site history, occupancy and conditions during WWII.

o The legacy of Allied military activity.

o Details of any known EOD clearance activity.

o The extent of any post war redevelopment.

o Scope of the current proposed works.

4.4. Sources of Information

BACTEC has carried out detailed historical research for this Explosive Ordnance Threat Assessment including accessing military records and archived material held in the public domain and in the MoD.

Material from the following sources has been consulted:

o The National Archives, Kew.

o Cambridgeshire Archives and Local Studies Centre.

o Relevant information supplied by Buro Four.

o Available material from 33 Engineer Regiment (EOD) Archive.



o BACTEC’s extensive archives built up over many years of research and hands-on Explosive Ordnance Disposal activities in the UK.

o Open sources such as published books, local historical records and the internet.

4.5. Reliability of Historical Records

4.5.1. General Considerations This report is based upon research of historical evidence. Whilst every effort has been made to locate all relevant material BACTEC cannot be held responsible for any changes to the assessed level of risk or risk mitigation measures based on documentation or other information that may come to light at a later date. The accuracy and comprehensiveness of wartime records is frequently difficult or impossible to verify. As a result conclusions as to the exact location, quantity and nature of the ordnance threat can never be definitive but must be based on the accumulation and careful analysis of all accessible evidence. BACTEC cannot be held responsible for inaccuracies or gaps in the available historical information.

4.5.2. Bombing Records During WWII considerable efforts were expended in recording enemy air raids. Air Raid Precautions (ARP) wardens were responsible for making records of bomb strikes either through direct observation or by post-raid surveys. However their immediate priority was to deal with casualties and limit damage, so it is to be expected that records are often incomplete and sometimes contradictory. Record keeping in the early days of bombing was not comprehensive and details of bombing in the early part of the war were sometimes destroyed in subsequent attacks. Some reports may cover a single attack, others a period of months or the entire war. Records of raids that took place on sparsely or uninhabited areas were often based upon third party or hearsay information and are not always reliable; records of attacks on military or strategic targets were often maintained separately from the general records and have not always survived.

5. The Site

5.1. Site Location The site is located just north and east of the villages of Alconbury, Little Stukeley and Great Stukeley in Cambridgeshire. It is mostly bound by agricultural fields however a railway line is present immediately east and the A1 and B1043 border the site to the south-west. The site is centred on the approximate National Grid Reference: 521572, 276540 Site location maps are presented in Annex A.

5.2. Site Description The study area is currently occupied by the majority of RAF Alconbury airbase. This non-operational facility is currently used for storage and also incorporates non-military centres such as a Police Dog Training facility and Alconbury Driving Centre. The site boundary currently includes runways, taxi ways, dispersal pans, numerous hangars, a WWII-era technical site, a post-WWII bomb dump, many other ancillary buildings and also a large agricultural area to the south-east of the base. A recent aerial photograph showing the boundary of the site area is presented in Annex B.

6. Scope of the Proposed Works A large mixed use development is proposed over the entire site. Note however that many parts of the site will not require intrusive work as they will become open spaces or woodland.



No precise details regarding the types and depth of the proposed intrusive works were available during the production of this report.

A proposed site plan is presented in Annex C.

7. Ground Conditions

The British Geological Survey Map Sheet 187 (not included) indicates that the whole site is immediately underlain by superficial Till deposits (Diamicton) with Oxford Clay Formation Mudstone bedrock to depth. Given the history of the site, localised areas of made ground are anticipated. Several BGS borehole logs within the study area indicate approximately 10m of very stiff dark grey glacial clay above the top bedrock layer.

8. Site History

8.1. Mapping A 1:10,560 scale OS map dated 1902 shows the site to be unoccupied and situated within a wider area of agriculture with several farms. A 1952 OS map of the same scale shows no change to the site. However a small scale WWII-era site plan of RAF Alconbury, presented in Annex D, confirms the airfields existence during WWII and therefore it appears the 1952 OS map has censored the airbase. A 1975 1:2,500 scale OS map shows all the airfield structures and buildings. The aircraft hangar areas and access roads appear to have a different footprint to that shown on the recent aerial photograph and the current bomb dump area is censored but shown to be part of the airfield. The far western corner of the site is occupied by buildings typical in appearance to barrack blocks. These structures are not the same as those that currently occupy this part of the site and therefore at least one phase of redevelopment/expansion has therefore taken place at RAF Alconbury in the post-WWII period.

8.2. History of RAF Alconbury1

8.2.1. RAF Use 1938 - 1942 In 1938, the Air Ministry acquired approximately 150 acres of open meadowland at Alconbury Hill for use as a satellite airfield. After a minimal amount of construction, RAF Alconbury was tested in May 1938 when No. 63 Squadron, the first to be equipped with the Fairey Battle light bomber, flew in from its home station of RAF Upwood. During this period, RAF Alconbury consisted of a few wooden huts but plans were made to provide both refuelling and rearmament facilities. In September 1939 Alconbury became RAF Wyton's satellite under No. 2 Group, Bomber Command. Squadrons 15 and 40 became stationed at Alconbury and converted from Battles to Bristol Blenheim bombers, with their first operations over occupied Europe beginning in May 1940. In late 1940 an expansion of RAF Alconbury commenced to upgrade its facilities from a satellite airfield to a fully operational bomber station. A 1,375 yard main concrete runway, an encircling perimeter track and 30 pan type hard-standings were constructed. The technical site on the north-west side was expanded where a single T2 hangar was also erected. A second T2 was sited adjacent to the hard-standing complex east of the runway. Personnel accommodation was provided to the south-west side of the A14, around Alconbury House which had been requisitioned earlier. No. 40 Squadron brought its Wellingtons to Alconbury in February 1941 and operated on night raids until the autumn. Targets were the industrial areas of Germany but also the German

1 M. J. F. Bowyer, Action Stations, 1980 and R. A. Freeman, Airfields of the Eighth, 1997



navy in their French Atlantic ports. Operations from Alconbury with No. 3 Group continued until August 1942 when the RAF relinquished the airfield.

8.2.2. USAAF WWII Use 1942 - 1945 In May 1942, RAF Alconbury was allocated to the United States Army Air Force (USAAF) following their entry into the war. It was designated by the USAAF as Station 102. The first USAAF unit to be activated at Alconbury was the 357th Air Services Squadron on 18th August 1942. To bring the station up to Class A airfield standards, the runways were extended, 26 hard-standings were added and two additional T-2 type maintenance hangars were constructed. The commercial buildings and barracks were dispersed in nearby farmland to the south-east of the airfield on the other side of the A14, with the bomb and ammunition stores sited on the opposite side, to the north. In addition, two underground gasoline storage facilities, with a total capacity of 216,000 gallons were situated at points adjacent to the perimeter track, but at some distance from the explosive storage area. At one frying-pan hard-standing on the north side of the airfield, a 25ft high earth shooting-in butt was constructed. During its WWII USAAF occupation, the station was home to four squadrons of B-24 Liberator aircraft of the 93rd Bomb Group (heavy) which flew missions against Bay of Biscay U-Boat pens, and engineering works in France. The B-17 Flying Fortress equipped 92nd Bombardment Group (heavy) transferred to Alconbury in January 1943 and engaged in bombing strategic targets, such as shipyards, ball-bearing plants, aircraft factories, etc. Four months later the 95th Bombardment Group also arrived. During this time the group made repeated attacks against V-weapon sites and airfields in France. On 27th May ground personnel were arming a B-17 in the dispersal area when, inexplicably, a 500lb bomb detonated. The explosion, in turn, set off several other bombs. 18 men were killed, 21 were injured and four B-17s were completely destroyed on the ground. 11 other B-17s were damaged. Several other bombardment, pathfinder and electronic warfare groups were also stationed at Alconbury for short periods during WWII. The latter of which used a number of P-38 fighter bombers as well as B-24 Liberators. During 1943 and 1944 non-operational activity increased at RAF Alconbury with development, testing and training carried out on new radar and navigational technologies. During 1943 the 2nd Strategic Air Depot was constructed on the eastern side of the airfield. This facility served the B-17 groups of the 1st Air Division as a major maintenance base. Operational bomber missions ceased at RAF Alconbury at the end of April 1945 with the majority of squadrons departing soon after. By November 1945 the base had been handed back to the RAF and was placed in caretaker status until 1951.

8.2.3. USAF Cold War Use 1953 – Present With the threat from the Soviet Union increasing the U.S again increased its air presence in Europe and RAF Alconbury was again turned over to the now independent United States Air Force (USAF). The station however required upgrading, which involved strengthening and extension of the runways, new aircraft standings and access tracks. The first units to be stationed at the base were those of the 47th Bombardment Wing, flying small jet engine bombers. In the 1950s the 42nd Troop Carrier Squadron and 53rd Weather Reconnaissance Squadron were based at Alconbury however the longest serving unit at Alconbury was the 10th Tactical Reconnaissance Wing (TRW) which arrived in 1959 and was disbanded 34 years later. The advent of reconnaissance satellites made the need for tactical recon less necessary by the mid 1970s. This, along with the need for budget reductions caused the reduction in the numbers of front line tactical recon aircraft. In the 1980s A-10s were assigned to Alconbury giving the 10th TRW a new close air support mission, however the majority of the aircraft at the base remained multi-role, recon fighters. In the early 1980s the 17th Reconnaissance Wing, flying high altitude U-2 spy planes, was activated at Alconbury. These new aircraft necessitated the need for extra facilities such as prefabricated ‘Ready Sheds’, thirteen extra-wide hardened aircraft shelters, a squadron headquarters, a massive Avionics and Photography Interpretation Centre, and new concrete aprons and taxiways.



In May 1993, as part of the drawdown of American forces in Europe, activities at Alconbury were significantly reduced. The airfield area and associated infrastructure were returned to the MoD on 30th September 1995 however the main base support areas were retained under USAF control and are currently administered by the 423rd Air Base Group.

9. The Threat from Allied Military Ordnance

9.1. RAF Station Contamination

9.2. General RAF Alconbury was in use as a military base from 1938-1995. During WWII it was predominantly used by the USAAF for high altitude, heavy bombardment of targets in occupied Europe. As such there is still a residual threat of ordnance contamination on site as items of explosive ordnance would have been stored, used and potentially disposed of at the airfield. In the post-WWII period the base was continuously used by the USAF during the Cold War. Although no state of war was ever realised during this period the base remained operational and therefore aircraft munitions were stored and possibly tested at Alconbury. It should be noted that UXO is regularly encountered on former MoD property by the public or the construction industry and the finds are usually of WWII vintage. If UXO remains at RAF Alconbury it too is likely to be from WWII because the frequency and intensity of operations during this period, coupled with a generally more relaxed attitude towards health and safety meant that items of UXO were more likely to be misplaced or buried. Furthermore, it is known that due to the swift departure of USAAF units from British bases following the end of WWII, American personnel left behind or buried large quantities of equipment and surplus munitions. This has been substantiated by post-WWII archaeological digs at USAAF sites such as Maybread in Norfolk2. The following is a list of the potential sources/activities that could have lead to UXO contamination at RAF Alconbury during WWII.

9.3. Ground Defensive Positions During WWII RAF airfields were typically fortified by pillboxes, defence huts and weapons pits. Pillboxes would have been of a brick or concrete construction and faced either away from the airfield for outer defence or towards the airfield for inner defence. During the period when the threat of enemy invasion was high, these positions would have been manned by armed ground personnel. Information taken from the English Heritage’s study of the WWII anti-invasion landscape of England (mapping the locations and types of existing defences around the country), does not record any existing WWII-era pillboxes within the site. However a 1946 Air Ministry RAF Alconbury site plan (presented in Annex E) obtained from the RAF Museum, records seven defence huts within the study area. As it is possible that ammunition/weapons were kept at these posts, the risk of UXO contamination is slightly elevated at those localities.

9.3.1. Anti-Aircraft Artillery Gun Emplacements At the start of WWII two types of AAA guns were deployed: Heavy Anti-Aircraft Artillery (HAA), using large calibre weapons such as the 3.7” QF (Quick Firing) gun and Light Anti-Aircraft Artillery (LAA) using smaller calibre weapons such as 40mm Bofors gun. All RAF airfields were defended by light anti-aircraft batteries which were usually dispersed around the airfield in isolated positions. However the RAF Alconbury site plan does not record any LAA batteries within or in close proximity to the site. LAA shells were high explosive (HE) projectiles, fitted with a contact fuze to make them explode on impact. If these shells failed to strike an aircraft, they would eventually fall back to earth. This type of ordnance is not likely to have had great penetration ability, and the majority of unexploded AAA shells are found close to WWII ground level or in made ground.

2 www.stripes.com/news/europe/uk/briton-digs-up-remnants-of-a-fierce-time



9.4. Home Guard Training The Home Guard (HG) was a defence organisation of the British Army, operational between 1940 and 1944. It comprised 1.5 million local volunteers, otherwise ineligible for military service, and acted as a secondary defence force, in case of enemy invasion. The HG guarded the coastal areas of Britain and other important facilities such as airfields, factories and explosives stores. Due to the pre-WWII construction of RAF Alconbury and its geographically significant position, in the south-east of England, it is considered likely that the airbase would have been used for HG anti-invasion training. The operational log books of other south-eastern RAF airfields indicate that anti-invasion training exercises in and around the grounds of the stations were regular carried out. RAF records also indicate that bases like Alconbury were occasionally used by British and Commonwealth army units being trained in enemy airfield capture. Such activities could have resulted in UXO contamination within the site boundary.

9.5. Ordnance/Explosives Storage and Disposal During WWII a range of ordnance would have been stored. Broadly speaking this would have included: o LSA and SAA - issued to security personnel/Home Guard.

o Light Anti-Aircraft Projectiles – issued to airfield AA regiments.

o .303” and .50” aircraft machine gun ammunition, air-delivered HE bombs, air-delivered

incendiaries and air-delivered practice bombs – handled by RAF and USAAF ground crews.

The RAF Alconbury 1946 site plan confirms the presence of the WWII-era bomb dump within the northern part of the study area. The bomb dump comprised HE bomb stores, Incendiary bomb stores, pyrotechnics stores, small arms ammunition stores and fuze/component stores. There are also areas labelled fuzing points, were the bombs were fuzed immediately prior to being loaded onto the aircraft. Previous experience at similar sites suggests that the UXO threat is significant within historic bomb dump areas. As a result of UXO surveys, carried out by BACTEC at Aberdeen Airport (formerly RAF Dyce), a 60lb HE rocket warhead and some AAA projectiles were encountered within the area of the former bomb dump. The airfield technical site is also shown to have been located within the study area. This complex included two pyrotechnics stores, a defence hut and three armouries. The latter of which are where the aircraft machine guns (and/or ground defence weapons) and possibly ammunition were stored, maintained and repaired. Numerous dispersal pans are shown within the site boundary. It should be noted that these were often where planes would be loaded with ammunition and bombs and therefore it is possible that munitions could have been misplaced or neglected in these locations; subsequently becoming buried.

Anecdotal accounts suggest that unwanted or unused ordnance on WWII air stations would often be burnt, buried or otherwise disposed of within peripheral parts of the facility or in the immediate surrounding area. This is evidenced by the discovery, by BACTEC, of various items of UXO at former WWII-era RAF airfields such as RAF Biggin Hill and RAF Moreton-in-Marsh. At the latter a WWII-era burning pit was encountered, which consisted of partially burnt munitions and other explosive materials. Furthermore BACTEC recently discovered British WWII-era HE bombs near the perimeter of RAF Oakington (a WWII Bomber Command station) see Annex F, as well as items of land service ammunition.

9.6. Practice Bombing

Operational RAF airfields which were home to squadrons with a low altitude bombing capability usually had a practice bombing target situated in an open, peripheral part of the airfield. During the early RAF occupation of the site light bombers was stationed at Alconbury and it is possible therefore that low level bombing practice was carried out at the airfield in preparation for the Battle of France in 1940.



The high altitude bombing carried out by the USAAF heavy bombardment groups however required larger, more remote ranges and it is likely therefore that, in line with other airfields in the region, aircraft from Alconbury carried out this training at Orford Ness range, on the eastern Suffolk coast. The possibility of encountering a practice bomb however cannot be entirely discounted as they may have been stored at the airbase.

9.7. Aircraft Weapons Testing

WWII airfields generally had firing ranges, test butts and other similar measures in place to test aircraft machine guns/cannons. Potential contamination around ranges would include live rounds, other munitions and heavy metals such as lead, antimony and barium. The 1946 RAF Alconbury site plan records a shooting-in butt and a smaller machine gun range in the northern part of the site.

9.8. Pipe Mines/Demolition Charges Pipe mines were deployed under the runways and significant buildings of some of the RAF airfields during the early part of WWII and were designed to destroy these installations in the event of invasion. Although the airfield was operational during the period of possible invasion, BACTEC’s database does not list RAF Alconbury as one of the facilities that was mined.

10. Threat Posed By Allied Explosive Ordnance

10.1. General The long life span of RAF Alconbury, its pre-WWII construction and the fact it was home to numerous differing squadrons from two country’s air forces means that both the quantity and variety of munitions utilised historically at RAF Alconbury is vast. The types of UXO most likely to be encountered on site (i.e WWII-era UXO) are listed below.

10.2. Small Arms Ammunition (SAA) The most likely type of ordnance to be encountered on site are items of SAA (bullets), especially .303” and .50” machine gun ammunition. The former of which were used on RAF aircraft machine guns and the latter were used by the American bombers. Even if an item such as this functioned however, the explosion would not be contained within a barrel and detonation would only result in local overpressure and very minor fragmentation from the cartridge case. Images of SAA are presented in Annex G.

10.3. Land Service Ammunition (LSA) 10.3.1. General

The term Land Service Ammunition covers all items of ordnance that are propelled, placed or thrown during land warfare. They may be filled or charged with explosives, smoke, incendiary or pyrotechnics. They can be broken into five main groups:

a. Mortars

b. Grenades

c. Projectiles

d. Rockets

e. Landmines

Unexploded or partially unexploded Mortars and Grenades are among the most common items of UXO encountered in the UK and therefore the possibility cannot be discounted that they were stores on site. They are commonly encountered in areas used by the military for training and are often found discarded on or near historic military bases. Examples of Grenades, Mortars and Home Guard weapons are presented in Annex H. Items of ordnance do not become inert or lose their effectiveness with age. Time can indeed cause items to become more sensitive and less stable. This applies equally to items



submerged in water or embedded in silts, clays or similar materials. The greatest risk occurs when an item of ordnance is struck or interfered with. This is likely to occur when mechanical equipment is used or when unqualified personnel pick up munitions.

10.3.2. Mortars A mortar bomb is a fin-stabilised munition, normally nose-fuzed and fitted with its own propelling charge (primary cartridge). Range is increased by adding extra propellant (augmenting charges). They are either HE or Carrier and generally identified by their tear-dropped shape (older variants however are parallel sided) and a finned ‘spigot tube’ screwed or welded to the rear end of the body housing the propellant charge. A mortar relies on a striker hitting a detonator for explosion to occur. It is possible that the striker may already be in contact with the detonator and that only a slight increase in pressure would be required for initiation. Discarded augmenting charges are often encountered around mortar firing areas/bases.

10.3.3. Grenades

A grenade is a short range weapon which may be thrown by hand, fired from the end of a rifle or projected/propelled from a special purpose grenade launcher. They are divided into two categories; HE and Carrier (generally smoke). As with mortars, a grenade striker may either be in contact with the detonator or still be retained by a spring under tension, and therefore shock may cause it to function. A grenade can have an explosive range of 15-20m. Common older variants have a classic ‘pineapple’ shape; modern grenades tend to be smooth-sided.

10.4. Miscellaneous When working on land used currently or historically by the military, all manner of explosive ordnance related items dating back over 100 years could be encountered. These may include practice (dummy) items, experimental weapons and other miscellanea such as detonators, flares and fuzes; the latter of which are known to have been stored at RAF Alconbury in the pyrotechnic store. It should be noted that, although small, detonators contain enough primary explosive to cause serious injury. Images of the most commonly encountered miscellaneous items are presented in Annex I.

10.5. Anti-Aircraft Artillery Shells These shells are frequently mistakenly identified as small German air-delivered bombs, but are differentiated by the copper driving band found in front of the base. Although the larger unexploded projectiles could enter the ground they did not have great penetration ability and are therefore likely to be found close to WWII ground level. With a HE fill and fragmentation hazard these items of UXO also present a significant risk if encountered. The smaller 40mm projectiles are similar in appearance and effect to small arms ammunition and, although still dangerous, present a lower risk. Pictures of AAA projectiles are presented in Annex J. Details of the most commonly deployed WWII AAA projectiles are shown below:

Gun type Calibre Shell Weight Shell Dimensions

3.7 Inch 94mm 12.7kg 94mm x 438mm

4.5 Inch 114mm 24.7kg 114mm x 578mm

40mm 40mm 0.9kg 40mm x 311mm

10.6. Practice Bombs

10.6.1. Bomb Characteristics

The standard aircraft practice bombs used in WWII generally emitted smoke as a spotting charge to indicate bombing accuracy. They were filled with sand, water or a chalk/lime solution. Practice bombs were not designed to cause any damage and therefore could be dropped in a variety of locations. Standard RAF practice bombs of the WWII-era were painted white overall with light green bands painted around the centre of the tail. Practice bombs containing an exploder had a red



band painted around the body. However bombs that have been in the ground for any period of time will begin to deteriorate and identification paint markings will have been lost. USAAF practice bombs were usually painted blue and used the same casing as the standard general purpose U.S 100lb live bomb. Diagrams and images of practice bombs used by the RAF and USAAF during WWII are presented in Annex K.

10.6.2. Explosive Content Typically practice bombs would contain the following explosive components:

o Detonator-burster – 10 grains fulminate of mercury.

o Smoke Filling – Usually 1lb of Titanium Tetrachloride, which forms a white cloud on exposure to the atmosphere upon detonation of tail cone.

o Flash Filling – 1lb mixture of gunpowder and magnesium turnings, which causes a brilliant white flash on detonation.

10.6.3. Hazards

The British aircraft practice bombs only contain a spotting charge which though small is nevertheless an explosive and therefore potentially hazardous. The main hazard is from a small localised explosion. However there is also the potential contamination from the toxic materials within the smoke bombs, which included stannic chloride, sodium phosphate and titanium tetrachloride.

10.7. Allied High Explosive and Incendiary Ordnance

As with German bombs, Allied bombs fall into two categories, HE and Incendiary. HE bombs were categorized and designated in accordance with particular roles. The bomb types most commonly used by WWII-era Allied air force squadrons would have been the general purpose and light case/medium capacity types. These types of weapons pose the biggest threat as they contain the largest HE content of any UXO that may still reside at Alconbury. For operations against large industrial/urban areas incendiary cluster bombs will have also been used. Examples of RAF and USAAF air-delivered bombs are presented in Annex L.

o General Purpose Bombs: As the name implies the GP bomb was designed with the widest range of objectives in mind. Consequently this type of bomb proved to be relatively ineffective for most specific purposes. Due to the thicker casings these munitions had a higher shrapnel effect. The GP family included several sizes ranging from 20lb to 4,000lb.

o Medium Capacity or Light Case Bomb: There were fewer weights in this category, 500lb, 1,000lb and 4,000lb. They had a higher charge to weight ratio (47%) than the general purpose bombs, due to thinner casings, and therefore tended to produce a proportionately larger blast effect.

o Specialist Bombs: A number of specialist bombs were developed for use during WWII, the most common of which and most likely to have been used by the RAF and USAAF heavy bombardment groups are the armour piercing and semi-armour piercing weapons. These were longer and slimmer than their general purpose counterparts, with a more pointed nose and a low charge to weight ratio. They came in five Allied weights, 450lb, 500lb, 1,000lb, 1,500lb and 1,600lb.

o Incendiary Bombs: Small incendiary bomblets, like their German counterparts, were designed to ignite on impact and spread their flammable contents. The 4lb IBs contained a small explosive charge to initiate flammable material within the bomb housing and hence these weapons pose a threat. They were commonly deployed in 500lb cluster bombs carried by heavy American bombers such as B-24 and B-17s.



11. The Threat from Aerial Bombing

11.1. General Bombing History of Huntingdonshire

11.1.1. First World War A consolidated WWI raid map of the UK showing air raids and naval bombardments is presented in Annex M. This map confirms that Huntingdonshire, in which the site was historically located, did not receive much attention by the German air force during WWI and no air raids are shown to have occurred in the Alconbury region. WWI bombs were generally smaller than those used in WWII and were dropped from a lower altitude, resulting in limited UXB penetration depths. Aerial bombing was often such a novelty at the time that it attracted public interest and even spectators to watch the raids in progress. When combined with the relative infrequency of attacks (compared to WWII levels) and an overall low bombing density the threat from WWI UXBs is considered low and will not be further addressed in this report.

11.1.2. Second World War

At the start of WWII, the Luftwaffe planned to destroy key military installations, including RAF airfields and Royal Navy bases, during a series of daylight bombing raids in southern and eastern England. After the Battle of Britain these tactics were modified to include both economic and industrial sites throughout the rest of the Britain. Targets included dock facilities, railway infrastructure, power stations, weapon manufacturing plants and gas works. As a result of aircraft losses, daylight raids were reduced in favour of attacking targets under the cover of darkness. As the war progressed the strategy changed to one of attempting to destroy the morale of the civilian population by the “carpet bombing” of London and other major UK cities such as Liverpool and Birmingham. Note however that no cities within Huntingdonshire were ever subjected to large scale Blitz bombing raids. By May 1941, concentrated attacks ceased as the Luftwaffe was diverted east to prepare for ‘Operation Barbarossa’, the invasion of the Soviet Union. From mid-1944 the “V-weapon” (for Vengeance) campaign began, using unmanned cruise missiles and rockets. The V1 (Flying Bomb or Doodlebug) and the V2 (Long Range Rocket) were launched from bases in Germany and occupied Europe. Although it is known that a small number of V1s landed in Huntingdonshire, none are thought to have occurred in the Alconbury region.

11.2. Aerial Delivered Ordnance in the Second World War

11.2.1. Generic Types of WWII German Air-delivered Ordnance The nature and characteristics of the ordnance used by the Luftwaffe allows an informed assessment of the hazards posed by any unexploded items that may remain today. Detailed illustrations of German air delivered ordnance are presented at Annex N. o HE Bombs: In terms of weight of ordnance dropped, HE bombs were the most frequent

weapon deployed. Most bombs were 50kg, 250kg or 500kg (overall weight, about half of which was the HE) though large bombs of up to 2,000kg were also used. HE bombs had the weight, velocity and shape to easily penetrate the ground intact if they failed to explode. Post-raid surveys would not always have spotted the entry hole or other indications that a bomb penetrated the ground and failed to explode and contemporary ARP documents describe the danger of assuming that damage, actually caused by a large UXB, was due to an exploded 50kg bomb. Unexploded HE bombs therefore present the greatest risk to present–day intrusive works.

o Blast Bombs/Parachute Mines: Blast bombs generally had a slow rate of descent and were extremely unlikely to have penetrated the ground. Non-retarded mines would have shattered on most ground types, if they had failed to explode. There have been extreme cases when these items have been found unexploded, but this was where the ground was either very soft or where standing water had reduced the impact. BACTEC does not consider there to be a significant threat from this type of munition on land.



o Large incendiary bombs: This type of bomb ranged in size from 36kg to 255kg and had a number of inflammable fill materials (including oil and white phosphorus), and a small explosive charge. They were designed to explode and burn close to the surface but their shape and weight meant that they did have penetration capability. If they penetrated the ground complete combustion did not always occur and in such cases they remain a risk to intrusive works.

o 1kg Incendiary Bombs (IB): These bombs, which were jettisoned from air-dropped containers, were unlikely to penetrate the ground and in urban areas would usually have been located in post-raid surveys. However, if bombs did not initiate and fell in water or dense vegetation, or became mixed with rubble in bomb damaged areas they could have been overlooked. Some variants had explosive heads and these present a risk of detonation during intrusive works.

o Anti-personnel (AP) Bomblets: AP bombs had little ground penetration ability and should have been located by the post-raid survey unless they fell into water, dense vegetation or bomb rubble.

o Specialist Bombs (smoke, flare, etc): These types do not contain HE and therefore a detonation consequence is unlikely. They were not designed to penetrate the ground.

11.2.2. German Air-delivered Ordnance Failure Rate Based on empirical evidence, it is generally accepted that 10% of the German HE bombs dropped during WWII failed to explode as designed. This estimate is probably based on the statistics of wartime recovered UXBs and therefore will not have taken account of the unknown numbers of UXBs that were not recorded at the time, and is probably an underestimate. The reasons for failures include: o Fuze or gaine malfunction due to manufacturing fault, sabotage (by forced labour) or

faulty installation.

o Clockwork mechanism failure in delayed action bombs.

o Failure of the bomber aircraft to arm the bombs (charge the electrical condensers which supplied the energy to initiate the detonation sequence) due to human error or equipment defect.

o Jettison of the bomb before it was armed or from a very low altitude. Most likely if the bomber was under attack or crashing.

War Office Statistics document that a daily average of 84 bombs which failed to function were dropped on civilian targets in Great Britain between 21st September 1940 and 5th July 1941. 1 in 12 of these (probably mostly fitted with time delay fuzes) exploded some time after they fell - the remainder were unintentional failures. From 1940 to 1945 bomb disposal teams dealt with a total of 50,000 explosive items of 50kg and over (i.e. German bombs), 7,000 AAA shells and 300,000 beach mines. These operations resulted in the deaths of 394 officers and men. However, unexploded ordnance is still regularly encountered across the UK (see recent press articles, Annex O-1).

11.2.3. UXB Ground Penetration

11.2.3.1. General Considerations The actual penetration depth of aerial delivered bombs into the ground will have been determined by the mass and shape of the bomb, the velocity and angle of the bomb on impact (dependent on the height of release) and the nature of the ground and ground cover; the softer the ground, the greater the potential penetration. Peat, alluvium and soft clays are easier to penetrate than gravel and sand. Bombs are brought to rest or are commonly deflected by bedrock or large boulders.

11.2.3.2. The “j” Curve Effect An air-dropped bomb falling from normal bombing altitude (say 5,000m) into homogeneous ground will continue its line of flight but turn in an upwards curve towards the surface as it



comes to rest. This offset from vertical is generally thought to be about one third of the penetration depth, but can be up to 15m depending on ground conditions or the bomb’s angle of impact.

11.2.3.3. Second World War Bomb Penetration Studies During WWII the Ministry of Home Security undertook a major study on actual bomb penetration depths, carrying out statistical analysis on the measured depths of 1,328 bombs as reported by Bomb Disposal, mostly in the London area. They then came to conclusions as to the likely average and maximum depths of penetration of different sized bombs in different geological strata. The median penetration of 430 x 50kg German bombs in London Clay was 4.6m and the maximum penetration observed for the SC50 bomb was 9m. They concluded that the largest common German bomb, 500kg, had a likely penetration depth of 6m in sand or gravel but 8.7m in clay. The maximum observed depth for a 500kg bomb was 10.2m and for a 1,000kg bomb 12.7m. Theoretical calculations suggested that significantly greater penetration depths were probable.

11.2.4. Initiation of Unexploded Bombs Unexploded bombs do not spontaneously explode. All HE requires significant energy to create the conditions for detonation to occur. In the case of unexploded German bombs discovered within the construction site environment, there are a number of potential initiation mechanisms: o Direct impact onto the main body of the bomb: Unless the fuze or fuze pocket is struck,

there needs to be a significant impact (e.g. from piling or large and violent mechanical excavation) to initiate a buried iron bomb. Such violent action can cause the bomb to detonate.

o Re-starting the clock timer in the fuze: Only a small proportion of German WWII bombs employed clockwork fuzes. It is probable that significant corrosion has taken place within the fuze mechanism over the last 60 years that would prevent clockwork mechanisms from functioning, nevertheless it was reported that the fuze in a UXB dealt with by 33 EOD Regiment in Surrey in 2002 did re-commence.

o Induction of a static charge, causing a current in an electric fuze: The majority of German WWII bombs employed electric fuzes. It is probable that significant corrosion has taken place within the fuze mechanism over the last 60 years such that the fuze circuit could not be activated.

o Friction impact initiating the (shock-sensitive) fuze explosive: This is the most likely scenario resulting in the bomb detonating.

Annex O-2 details UXB incidents where intrusive works have caused UXBs to detonate, resulting in death or injury and damage to plant.

11.3. Bombing of Alconbury

11.3.1. Second World War Overview During WWII Huntingdonshire was largely agricultural in character and did not contain any large cities or industrial centres that would have increased the likelihood of air raids. However, Huntingdonshire County Council’s ARP officers recorded at least 340 bombs in the county up to the end of 1940 and 510 by the end of August 1941. Most of the airfields in the region were USAAF stations that were built during 1943, after the main Blitz period of bombing in Britain, and are therefore unlikely to have been targeted. Bombing of the region is illustrated by a Huntingdonshire bombing density map, presented in Annex P. This map does not record any bombing incidents in the immediate Alconbury area however the nearest incident (comprising 8 HE bombs) is shown to have occurred near the village of Great Stukeley, adjacent to the site. Note that air raids at military facilities were not always reported/recorded in civilian ARP documents.



Due to the lack of significant targets, raids in the region may have been due to ‘tip and run’ incidents, whereby bombers approaching targets would jettison their bombs indiscriminately and return to base due to intense AAA fire or fighter interception. Due to its presence during the early war period RAF Alconbury was specifically targeted and it is known to have been bombed. Records of bombing incidents in the civilian areas were collected by the Air Raid Precautions wardens and collated by the Civil Defence Office. Records would be in the form of typed or hand written incident notes, maps and statistics.

11.3.2. Second World War Bombing Statistics The table below summarises the quantity of German bombs recorded in the county up until 31st August 1941:

Record of German ordnance dropped in Huntingdonshire up until 31st August 1941

High Explosive bombs 510

Items of Unexploded Ordnance 73

Parachute Mines 0

Oil Bombs 26

Source: Cambridgeshire Archives and Local Studies Centre (Huntingdon Repository)

11.3.3. Site Specific Bombing

The original ARP written reports were not available from the Cambridgeshire Archives and Local Studies Centre (Huntingdon Repository) and therefore records may have been lost, discarded or destroyed in the post-war period. A third party source3 however does confirm three raids on RAF Alconbury during the early part of the war. o 16th September 1940 - No serious damage.

o 8th March 1941 – One Wellington bomber damaged.

o 11th June 1941 – One Wellington bomber damaged. These three raids resulted in 46 HE bombs being dropped on the airfield and immediate surrounding area. Note however that the locations of the bomb strikes is unknown.

11.3.4. Second World War Era Aerial Photographs WWII-era RAF aerial photography of the site and surrounding area was ordered from the National Monument Records Office, Swindon, however was not available in the timescale of this report. If these images exhibit any significant information Buro Four will be contacted immediately. Poorer resolution 1945 aerial photography was obtained from The GeoInformation Group and two images covering the entire site are presented in Annex Q. These images show the airfield in the immediate post-WWII period and record the airfield complex as it is shown on the 1946 RAF Alconbury site plan. Although of small scale, no obvious evidence of significant bomb damage is visible on site and no bomb craters are apparent in areas of open ground.

11.3.5. Abandoned Bombs A post-air raid survey of buildings, facilities and installations would have included a search for evidence of bomb entry holes. If evidence were encountered, Bomb Disposal Officer teams would normally have been requested to attempt to locate, render safe and dispose of the bomb. Occasionally evidence of UXBs was discovered but due to a relatively benign position, access problems or a shortage of resources the UXB could not be exposed and rendered safe. Such an incident may have been recorded and noted as an Abandoned Bomb.

3 C. Clifford & A. Akeroyd, Huntingdonshire in the Second World War, 2007



Given the inaccuracy of WWII records and the fact that these bombs were ‘abandoned’, their locations cannot be considered definitive, nor the lists exhaustive. The MoD states that ‘action to make the devices safe would be taken only if it was thought they were unstable’. It should be noted that other than the ‘officially’ abandoned bombs, there will inevitably be UXBs that were never recorded. BACTEC holds no records of officially registered abandoned bombs on or near the site.

11.3.6. Site Specific Bomb Penetration Considerations When considering an assessment of the bomb penetration at the proposed site the following parameters would be used:

o Geology – At least 10m of superficial glacial clay underlain by Mudstone bedrock.

o Impact Angle and Velocity – 80-90O from horizontal and 267 metres per second.

o Bomb Mass and Configuration – The 500kg SC (General Purpose) HE bomb, without retarder units or armour piercing nose. This was the largest of the common bombs used against Britain.

Taking into account the above-mentioned factors it has been assessed that a 500kg bomb would have had a maximum bomb penetration depth of up to 12m below WWII ground level. Penetration depth could potentially have been greater if the UXB was larger (though only 4% of German bombs used in WWII over Britain were of that size). Note that UXBs may be found at any depth between just below the WWII ground level and the maximum penetration depth.

11.4. Deductions Utilising the available historical bombing records as reviewed in section 11.3, it is possible to make an assessment of the likelihood that evidence of unexploded German air-delivered ordnance would have been noted on a site during the war and the incident dealt with or recorded at the time. Factors such as bombing density, frequency of access, ground cover, damage and failure rate have been taken into consideration.

11.4.1. Density of Bombing Bombing density is an important consideration for assessing the possibility that UXBs remain in an area. A very high density of bombs can for example result in increased levels of damage sustained to structures, greater likelihood of errors in record keeping and a higher risk that UXBs fell over the area. Huntingdonshire sustained a low density of bombing throughout WWII, with some 510 HE bombs dropped on the county up until 31st August 1941. This density however is known to have been locally higher in the vicinity of the site due to the presence of RAF Alconbury which was bombed on at least three occasions. During these raids at least 46 bombs were dropped.

11.4.2. Frequency of Access Unexploded ordnance at sites where human access was infrequent would have a higher chance of being overlooked than at those sites which were subject to greater occupancy. The importance of a site or facility to the war effort is also an important consideration as such sites are likely to have been both frequently accessed and are also likely to have been subject to post-raid checks for evidence of UXO. Levels of access will have been variable across different parts of the site. The aircraft hangars, the bomb dump, dispersal pans, technical site, communal site and their immediate environs would have all been regularly frequented during the war. Furthermore, with the exception of the dispersal pans, these areas are also likely to have been subject to checks for UXO following the air raids. During the attacks it is considered highly likely that AA defences at the airfield would have engaged the enemy bombers. This coupled with the relatively small number of aircraft involved suggests it is likely that a UXB strike would have been observed. The remainder of the study area, the airfield peripheries and the agricultural area to the south-east, will have been accessed to a much lesser degree. The fields outside the airbase



perimeter would have been in use for cultivation or livestock. Access would have been infrequent/irregular and therefore it is conceivable that a UXB strike could have gone unobserved.

11.4.3. Ground Cover The degree and type of groundcover present during WWII would have a significant effect on the visual evidence at ground level which may have indicated the presence of buried UXO. Parts of the study area were occupied by hard surfaced runway/dispersal pans and buildings onto which a UXB strike would have left obvious, observable evidence. The remainder of the airfield however would have been covered by rough grassland. In this area, as well as the worked fields to the south-east of the station perimeter, the identification of a UXB entry hole will have been less likely. Note that the entry hole of an SC 50 HE UXB, the most commonly deployed HE bomb, may have been as small as 20cm in diameter and therefore easily obscured by dense crops or soil debris (ploughed field). Also noteworthy is that during WWII German 1kg incendiary bombs were observed to penetrate to a significant depth when dropped into soft ground. The photograph presented in Annex R shows how such a sub-munition could have remained undetected in the post-war period.

11.4.4. Damage

If structures on a site have been subject to significant bomb or fire damage rubble and debris are likely to have been present; similarly a HE bomb strike on open ground is likely to have resulted in a degree of soil disturbance. Under such conditions there is a greater risk of the entry holes of unexploded bombs dropped during subsequent raids being obscured and going unnoticed. Immediate post-WWII RAF aerial photography of the site does not exhibit any large scale damage or bomb craters within the study area. An anecdotal account also describes only minor damage to two aircraft during the three air raids.

11.4.5. Bomb Failure Rate There is no evidence to suggest that the bomb failure rate in the vicinity of the site would have been different from the “approximately 10%” figure normally used.

12. Ordnance Clearance and Post-WWII Ground Works

12.1. General The extent to which any ordnance clearance activities have taken place on site or extensive ground works have occurred is relevant since on the one hand they may indicate previous ordnance contamination but also may have reduced the risk that ordnance remains undiscovered.

12.1.1. EOD Bomb Disposal and Clearance Tasks

A site specific request for information was made to the MoD Explosive Ordnance Disposal (EOD) Archive Information Office. This service however is suffering minor delays and the information was not available within the timescale of this report. When the report is received Buro Four will be contacted if any relevant information is included.

12.2. Post-War Redevelopment

In the post-war period the base has undergone various phases of development/expansion in line with the introduction of newer aircraft and associated technologies. The majority of this development has been the construction of a new bomb dump, new facility buildings and numerous large hangars with associated hard-surfaced access tracks and aprons.



13. The Overall Explosive Ordnance Threat Assessment

13.1. General Considerations Taking into account the quality of the historical evidence, the assessment of the overall threat to the proposed works from unexploded ordnance must evaluate the following risks:

o That the site was contaminated with unexploded ordnance

o That unexploded ordnance remains on site

o That such items will be encountered during the proposed works

o That ordnance may be activated by the works operations

o The consequences of encountering or initiating ordnance

13.2. The Risk that the Site was Contaminated with Unexploded Ordnance For the reasons discussed in sections 9 and 11 BACTEC believes that there is a risk from encountering explosive ordnance at the RAF Alconbury site. These reasons are summarised below. Allied UXO

o The site is partially situated within the historic perimeter of RAF Alconbury, a WWII-

era/Cold War-era airbase. Experience has shown that the ‘housekeeping’ at historic RAF/USAAF stations was often poor with unwanted or unused ordnance sometimes buried, burnt, lost or otherwise discarded within or in close proximity to the airfield perimeter. Furthermore, the requirement for a swift post-WWII USAAF exit from England meant that some American military equipment was simply abandoned, poorly disposed of or buried within or close to their bases.

o Previous BACTEC work on several former RAF stations has shown that the former bomb stores and dispersal pans/aircraft armament areas (where aircraft were loaded with weapons), have a higher risk of UXO contamination. As these features were/are located within the study area, the risk of encountering such munitions is elevated. BACTEC also recently exhumed WWII British HE bombs buried outside the perimeter of a former RAF Bomber Command base.

o 1946 RAF Alconbury site plans show that several defence huts, pyrotechnics stores, armouries and gunnery ranges were positioned around the airfield, away from the bomb dump. The locations of these features will also have a slightly heightened risk of UXO associated with them.

o Home Guard units and possibly regular army units are likely to have carried out guard duties and training within and in close proximity to the base. During such activities small arms ammunition and land service ammunition (grenades, mortars, etc) would have been issued to personnel, increasing the chance of UXO contamination.

o If UXO remains at RAF Alconbury it is more likely to be of WWII-era because the frequency and intensity of operations during this period, coupled with a generally more relaxed attitude towards health and safety meant that items of UXO were more likely to be misplaced or buried. Although RAF/USAF rules and regulations regarding handling and storage of munitions have become increasingly more stringent in the post-WWII period, the possibility cannot be discounted that American UXO from the period 1953 – 1995 could be encountered on site, particularly in the current bomb dump facility, to the north.

German UXO

o Due to its rural nature, Alconbury was situated in an area of low bombing density throughout WWII. The only viable Luftwaffe targets in the region were several RAF airfields including that which occupied the site. The presence of this facility did locally raise the bombing density however. Records indicate that three small scale air raids were made on the airbase between 1940 and 1941. These attacks resulted in 46 HE bombs recorded on and close to the airfield.



o Levels of access will have been variable across different parts of the site. Generally the

main airfield site and communal area to the west would have been regularly frequented during the war. Furthermore, the buildings are likely to have been subject to checks for evidence of UXO, that would have been fairly obvious, following the air raids. During the raids it is considered highly likely that AA defences at the airfield would have engaged the attackers. This coupled with the small number of aircraft involved suggests it is likely that a UXB strike would have been observed.

o The airfield peripheries and the agricultural area to the south-east will have been accessed to a much lesser degree. Therefore it is conceivable that a UXB strike could have gone unobserved and an entry hole would have been easily obscured; note that the entry hole of an SC 50 HE UXB, the most commonly deployed HE bomb, may have been as small as 20cm in diameter and therefore easily obscured by dense crops or soil debris (ploughed fields).

o Immediate post-WWII RAF aerial photography of the site does not exhibit any large scale damage or bomb craters within the study area. An anecdotal account also describes only minor damage to two aircraft during the three air raids.

13.3. The Risk that Unexploded Ordnance Remains on Site

For the large part there has not been any significant redevelopment of the airfield since it became a non-operational base in 1995. There has however been some development within the airfield in the post-WWII period and therefore the risk of encountering shallow buried UXO (such as SAA, 1kg German incendiaries, AAA shells and USAAF munitions) in these areas will have been partly mitigated since any such items may have been discovered during excavations. However the risk from deep-buried German HE UXBs will only have been mitigated at the precise locations of and down to the depth of any post-war deep excavations or pile foundations. Ploughing and re-working of farmland has been known to exhume shallow buried items of UXO, however purposely buried UXO has also been encountered at depths below that of normal ploughing methods. Therefore the risk of encountering UXO at any depth within the south-eastern part of the study area will not have been fully mitigated.

13.4. The Risk that Ordnance may be Encountered during the Works The most likely scenarios under which a UXO could be encountered during construction works is during piling, drilling operations or bulk excavations for basement levels. The overall risk will depend on the extent of the works, such as the numbers of boreholes/piles (if required) and the volume of the excavations. Since an air-dropped bomb may come to rest at any depth between just below ground level and its maximum penetration depth there is also a chance that such an item could be encountered during shallow excavations (for services or site investigations) into the original WWII ground level. However, at shallow depths, there is a greater risk of encountering smaller items of UXO such as SAA, LSA, small incendiaries, AA shells and other buried or partially burned munitions.

13.5. The Risk that Ordnance may be Initiated The risk that UXO could be initiated if encountered will depend on its condition, how it is found and the energy with which it is struck. The most violent activity on most construction sites is percussive piling; however UXO may initiate on impact with any heavy machinery.

13.6. The Consequences of Encountering or Initiating Ordnance Clearly the consequences of an inadvertent detonation of UXO during construction operations would be catastrophic with a serious risk to life, damage to plant and a total site shutdown during follow-up investigations. Since the risk of initiating ordnance is comparatively low if appropriate mitigation measures are undertaken, the most important consequence of the discovery of ordnance will be



economic. This would be particularly so in the case of high profile locations and could involve the evacuation of the public. The unexpected discovery of ordnance may require the closing of the site for any time between a few hours and a week with a potentially significant cost in lost time. Note also that the suspected find of ordnance, if handled solely through the authorities, may also involve loss of production since the first action of the Police in most cases will be to isolate the locale whilst awaiting military assistance, even if this turns out to have been unnecessary.

13.7. BACTEC’s Assessment Taking into consideration the findings of the study, BACTEC considers the risk across the study area to be heterogeneous and can therefore be subdivided into three risk zones; Low/Medium, Medium/High and High Risk Zones. A Risk Map illustrating these zones is presented in Annex S. Low/Medium Risk Zone This zone comprises the south-eastern section located outside the airbase perimeter. Level of Risk

Type of Ordnance Negligible Low Medium High

Allied Bombs – live *

Allied Bombs – practice *

Land Service and Small Arms Ammunition

*

Anti-Aircraft Artillery Projectiles *

German HE Bombs *

German 1kg Incendiary Bombs *

Medium/High Risk Zone This zone represents the majority of the airbase complex including the late Cold War-era bomb dump. Level of Risk





*


German HE Bombs *




High Risk Zone This zone comprises the area of the former WWII-era bomb dump. Level of Risk





*


German HE Bombs *


14. Proposed Risk Mitigation Strategy

14.1. General Due to the large scale and complexity of the RAF Alconbury redevelopment BACTEC suggests that a meeting be held with Buro Four in order to create a bespoke risk mitigation strategy for the site, prior to intrusive works. This is likely to include the following mitigation measures:

14.2. Potential Risk Mitigation Measures

All Risk Zones o Explosive Ordnance Safety and Awareness Briefings to all personnel conducting

intrusive works: A specialised briefing is always advisable when there is a possibility of explosive ordnance contamination. It is an essential component of the Health & Safety Plan for the site and conforms to requirements of CDM Regulations 2007. All personnel working on the site should be instructed on the identification of UXB, actions to be taken to alert site management and to keep people and equipment away from the hazard. Posters and information of a general nature on the UXB threat should be held in the site office for reference and as a reminder.

o The provision of Unexploded Ordnance Site Safety Instructions: These written instructions contain information detailing actions to be taken in the event that unexploded ordnance is discovered. They are to be retained on site and will both assist in making a preliminary assessment of a suspect object and provide guidance on the immediate steps to be taken in the event that ordnance is believed to have been found.

Medium/High and High Risk Zones only o On greenfield areas only: Non-Intrusive Magnetometer Survey and target

investigation ahead of any intrusive works – This survey is carried out using caesium vapour magnetometers linked to a data logger. Data is interpreted using advanced proprietary software which is capable of modelling the magnetic anomalies for mass, depth and location, thus providing information which can be used to locate discrete buried objects that may be ordnance. The system will typically locate buried ordnance to a depth of 4m for a 50kg bomb (the smallest HE bomb used by the Luftwaffe) and deeper for larger bombs. Additionally the survey will locate any buried services with a magnetic signature, will indicate areas of gross magnetic “contamination” (which may indicate unknown underground obstructions) and provide information on archaeological features. The technique is not appropriate in a brownfield or built environment; where such a technique is not appropriate, an EOD engineer presence on site is recommended.



In developed areas, including areas of hard-standing, roads, made ground, buildings, etc a Non-Intrusive Magnetometer Survey is inappropriate due to high levels of background ‘noise’. In these areas the following is recommended:

o Explosive Ordnance Disposal (EOD) Engineer presence on site to support shallow intrusive works: When on site the role of the EOD Engineer would include; monitoring works using visual recognition and instrumentation and immediate response to reports of suspicious objects or suspected items of ordnance that have been recovered by the ground workers on site; providing Explosive Ordnance Safety and Awareness briefings to any staff that have not received them earlier and advise staff of the need to modify working practices to take account of the ordnance threat, and finally to aid Incident Management which would involve liaison with the local authorities and Police should ordnance be identified and present an explosive hazard.

In making this assessment and recommending these risk mitigation measures, the available historic sources and proposed works outlined in the ‘Scope of the Proposed Works’ section were considered. Should the planned works be modified or additional intrusive engineering works be considered, BACTEC should be consulted to see if a re-assessment of the risk or mitigation recommendations is necessary.

BACTEC International Limited 19th April 2012



Bibliography The key published documents consulted during this assessment are listed below:

o R. A. Freeman, Airfields of The 8th – Then and Now, 1978

o Bates, H, E., Flying Bombs over England, Frogletts Publications Ltd. 1994.

o Bowyer,M, J, F., Action Stations Revisited: No 1 Eastern England, Crecy Publishing. 2000.

o Dobinson, C., AA Command: Britain’s Anti-Aircraft Defences of the Second World War, Methuen. 2001.

o Fegan, T., The Baby Killers’: German Air raids on Britain in the First World War, Leo Cooper Ltd. 2002.

o Fleischer, W., German Air-Dropped Weapons to 1945, Midland Publishing. 2004.

o Jappy, M. J., Danger UXB: The Remarkable Story of the Disposal of Unexploded Bombs during the Second World War. Channel 4 Books, 2001.

o Osborne, M., 20th Century Defences in Britain. The East Midlands. Concrete Publications. 2003.

o Price, A., Blitz on Britain, The Bomber Attacks on the United Kingdom 1939 – 1945, Purnell Book Services Ltd. 1977.

o Ramsey, W., The Blitz Then and Now, Volume 1, Battle of Britain Prints International Limited. 1987.



o Whiting, C., Britain Under Fire: The Bombing of Britain’s Cities 1940-1945, Pen & Sword Books Ltd. 1999.

RAF Alconbury

Explosive Ordnance Threat Assessment Report

AnnexA

Annex A: Site Location Maps

Produced by BACTEC International Limited Report 3870TAFor Buro Four

RAF Alconbury


AnnexB

Annex B: Recent Aerial Photograph of the Site


Annex

North

Recent Aerial Photograph of the SiteB

Report Reference: Client:Approximate site boundaryBuro Four

Project:

p

Source:

pp y

RAF Alconbury

Buro Four

3870

Google Earth TM Mapping Services

RAF Alconbury


AnnexC

Annex C: Proposed Site Plan


Annex

North

Proposed Site PlanC

Report Reference: Client:Approximate site boundary

Buro Four

Project:

p

Source: Buro Four

RAF Alconbury

Buro Four

3870

RAF Alconbury


AnnexD

Annex D: WWII-era RAF Alconbury Site Plan


AnnexD

North

WWII-era RAF Alconbury Site Plan

Approximate site boundary

Project:

Report Reference: Client:

Source:

3870TARAF Alconbury

Buro Four

USAAF

RAF Alconbury


AnnexE

Annex E: 1946 RAF Alconbury Site Plan


Annex1946 RAF Alconbury Site Plan E-1

North

Northern Part

Bomb Dump

Communal Site

Airfield Technical

Site

Armoury

Defence Hut

Bomb Dump

Four bomb stores, three SAA stores, six pyrotechnic/incendiarybomb stores one LC bomb store one flame float store and

Pyrotechnic Store

Machine gun/cannon range or shooting-in butt

bomb stores, one LC bomb store, one flame float store andseveral auxiliary structures.

Report Reference: Client:Buro Four


Project:

p

Source: RAF Museum, Hendon

RAF Alconbury

Buro Four

3870

Annex1946 RAF Alconbury Site PlanE-2

North

Southern Part

Maintenance Depot

Maintenance Depot


ArmouryArmoury

Defence Hut

Pyrotechnic Store

Report Reference: Client:Buro Four

Machine gun/cannon range / shooting-in butt


Project:

p

Source: RAF Museum, Hendon

RAF Alconbury

Buro Four

3870

3870 ta raf alconbury, cambridgeshire

Documents