How to look for records of... Bomb Census survey 1940-1945

In September 1940, the government started to collect information relating to damage sustained during bombing raids. This was known as the ‘Bomb Census’. Initially, only information relating to London, Birmingham and Liverpool was collated, but by September 1941 the Bomb Census had been extended to cover the rest of the UK.

Its purpose was to provide the government with a complete picture of air raids taking place to assess raid patterns, types of weapon used and the damage caused, in particular to strategic services, such as railways, shipyards, factories and public utilities.

Information was gathered locally by police, air raid wardens and military personnel. They noted where, when and what types of bombs had fallen during an air raid and passed this on to the Ministry of Home Security Bomb Census Organisation where regional technical officers plotted the positions of the bombs onto maps.

These bomb plots, along with the information gathered locally, were passed to the Ministry of Home Security Research and Experiments Branch.

The information was digested, summarised and sometimes collated with intelligence from other sources. The reports were distributed to the Cabinet, Air Ministry, local authorities and to government departments with responsibility for civil defence.

The Ministry of Home Security divided the UK into 12 civil defence regions and information about bomb damage was coordinated through these regions. London (region 5) was sub-divided into groups and further divided by borough. Appendix 1 maps out the civil defence regions and sub-groups, listed below:

1. Northern (HQ Newcastle-upon-Tyne)
2. North Eastern (HQ Leeds)
3. North Midland (HQ Nottingham)
4. Eastern (HQ Cambridge)
5. London
6. Southern (HQ Reading)
7. South Western (HQ Bristol)
8. Wales (HQ Cardiff)
9. Midland (HQ Birmingham)
10. North Western (HQ Manchester)
11. Scotland (HQ Edinburgh)
12. South Eastern (HQ Tunbridge Wells)

Northern Ireland seems to have been outside the regional structure but The National Archives does hold a small number of records relating to bomb damage in Northern Ireland.

HO 193/90 and chapter 7 of HO 191/203 include some information on the historical background to the Bomb Census survey.

3. Key records of the Bomb Census

There are three main types of records that made up the Bomb Census:

3.1 Bomb Census reports

Of particular significance among the records are the Bomb Census reports. These were mostly made up of forms called BC4s and were completed by the Research and Experiments Branch of the Ministry of Home Security.

BC4 forms contain the following information:

• date and time that the bomb fell
• type and size of bomb
• whether the bomb exploded
• brief description of damage caused, including the size of crater
• information on air raid warnings
• casualty statistics
• map sheet reference

Casualties are categorised as killed (K); seriously injured (S/I); or lightly injured (L/I) but do not give their names (see section 6 for advice on searching for casualties by name).

The BC4 form is often accompanied by a tracing of a map showing features such as the road layout, and the point of impact of the bomb.

The bombs in each raid are numbered in sequence on the BC4 form.

3.2 Bomb Census maps

The National Archives has maps and tracings for all of the London civil defence region, but far fewer for provincial towns and cities.

There are a variety of maps showing different analyses of the bomb fall.

Information is sometimes plotted directly onto an Ordnance Survey map and sometimes on tracings which overlay the maps.

Incendiary bombs are shown as a hatched area as they were impossible to count. Other bombs can be marked as small black dots or coloured circles denoting the day of the week the bomb fell.

On most maps the bombs are numbered to show the sequence in which they fell. The bomb number, date and time of the bomb is marked in the margin.

Accumulative maps show bombs dropped over periods varying between one night and a month.

3.3 Air raid damage files

Some air raid incidents were followed up with a more detailed investigation. There are over 1,000 files containing reports on specific towns or London boroughs which typically contain:

• copies of form BC4
• detailed technical report on the effects of the bomb and the extent of damage caused
• analysis of the size and type of bomb
• plans of buildings showing damage
• photographs

Some files provide a general analysis of bomb damage and its effects on industry, transport and public utilities, and some transcripts of interrogation of enemy personnel.

4. How to search for Bomb Census records

A search for documents at The National Archives begins in our online catalogue.

Every document we hold is listed in our catalogue by a unique reference (a code made up of letters and numbers). You will need to identify the unique reference to be able to see the record.

All document references begin with a department letter code. The records of the Ministry of Home Security Bomb Census Organisation, which administered the Bomb Census, fall under the umbrella of the Home Office, the department code for which is HO. Each department is then made up of multiple record series.

The following sections of this guide explain the key record series within the HO department that contain the Bomb Census. Searching within these record series will help you to target your catalogue searches more precisely to locate a full document reference.

Records of the Bomb Census are not viewable online so to see them you will have to either visit us in Kew or order copies.

4.1 Bomb Census reports

Bomb Census reports are in the record series HO 198.

These are organised according to the type of bomb that fell, as follows:

• bombs dropped from piloted aircraft: HO 198/1-73
• V1 flying bombs: HO 198/74-102
• V2 long range rockets: HO 198/103-109

Then arranged by civil defence region and then by date of the air raid.

Bombs dropped from piloted aircraft in London (region 5) are further divided into groups. Knowing this sub-group will help to narrow your search down (see Appendix 1).

V1 flying bombs and V2 long range rockets are not split into the sub-groups. If you know the date a bomb fell, this will help to narrow the results down.

If you do not know what type of bomb was dropped or a specific date, you may need to search in multiple documents.

4.2 Bomb Census maps

Bomb Census maps are in the record series HO 193.

These are also organised by the different types of bombs that were dropped and by date. Bombs dropped from piloted aircraft are divided into London raids and provincial raids:

• piloted aircraft in London raids: HO 193/1-11, HO 193/15-40and HO 193/84-87
• piloted aircraft in provincial raids: HO 193/55-67 and HO 193/73-81
• V1 flying bombs: HO 193/48-50
• V1 tracings to use with maps: HO 193/69-71
• V2 long range rocket maps: HO 193/48-50
• V2 tracings to use with maps: HO 193/72

For provincial towns and cities, the online catalogue mostly only lists the first and last place included. See Appendix 2 for the expanded list.

Alternatively, if you have a map sheet reference from a BC4 form, you can consult the printed catalogue, available in the reading rooms at The National Archives, which lists the relevant document per map sheet reference.

If a map sheet reference is not known, the printed catalogue also includes a map of Britain covered by grids which you can use to identify a numbered square. The numbered square, for example 56/20, is the basis of the map sheet reference.

If you do not know what type of bomb was dropped or a specific date, you may need to search across multiple maps and tracings.

4.3 Air raid damage files

Air raid damage files are in the record series HO 192.

Click on the following links relating to a specific civil defence region to browse the descriptions of the air raid damage files by place name or topic of the file:

1. Northern HO 192/75-128
2. North Eastern HO 192/129-163
3. North Midland HO 192/164-199
4. Eastern HO 192/200-327
5. London HO 192/328-809
6. Southern HO 192/810-861
7. South Western HO 192/862-923
8. Wales HO 192/924-931
9. Midland HO 192/932-946
10. North Western HO 192/947-956
11. Scotland HO 192/957-961
12. South Eastern HO 192/962-1094

For Northern Ireland, search our catalogue as described below.

4.4 Search for records using keywords

You can also search the catalogue using keywords and dates.

You can search any of the three key record series individually from the HO 198, HO 193 or HO 192 homepages. Alternatively, use the advanced search option to search across all three at the same time, placing HO 198, HO 193 and HO 192 in the reference boxes.

Use the following as keywords to search with:

• the name of a town
• a London borough
• a civil defence region or group number
• map sheet number
• a keyword such as ‘factory’, ‘shipyard’ or ‘airfield’

5. Other records of air raid attacks and damage

See the following record types, produced by branches of central government, for a broader picture of the effects of and responses to air raids.

5.1 Records of the Key Points Intelligence Directorate

‘Key points’ was the name used to refer to strategic targets such as factories, public utilities, service establishments and buildings of national importance.

The Key Points Intelligence Directorate of the Ministry of Home Security compiled and distributed information about attacks on these key points and produced reports on the damage sustained. These files include:

• general assessments and reviews of defence measures
• weekly reports summarising the damage to and effect on production
• daily damage reports giving the same information in tabular format

Search by year and month for reports in HO 201 or browse the 43 records in the series. Map tracings of air raid damage to key points are in HO 315 and are also only searchable by year and month.

5.2 Home Security War Room reports

These reports were made by the Home Security War Room and regional war rooms for the use of the Ministry of Home Security and other departments. They contain daily and weekly assessments of raids and damage. Arranged into ten records in the series HO 202, they are searchable only by report number range or date, so it’s easier to browse the series to locate one.

5.3 Home Security daily intelligence reports

These are reports received in the Home Security War Room summarising air raid damage and other information of importance to civil defence, collated for the benefit of the Minister, the Cabinet and other senior officials. Arranged into sixteen records in the series HO 203, they are searchable only by report number range or date, so it’s easier to browse the series to locate one.

6. Searching for casualties by name

Try searching on the Commonwealth War Graves Commission website to trace a record by name of someone killed by a bomb. Try variations of a name if your first search does not yield results. For example, Bert may be listed as Albert, Bill as William, and so on.

Alternatively, you can consult the printed volumes of the Civilian War Dead 1939-1945 register, published by the Imperial War Graves Commission (now the Commonwealth War Graves Commission). A copy is available at the library of The National Archives. There are eight volumes arranged by county and borough and include the full name of the casualty, their age, names of parents and/or spouse and when and where they were injured and died. Sometimes the injury occurred at a domestic address, but the casualty died later in a hospital in a different borough.

It may, alternatively, be worth searching online for ‘civilian war dead’ by county or London borough.

7. National Fire Service and Air Raid Precautions

For the first two years of the war, fires were dealt with by locally run Auxiliary Fire Services, staffed by men who were unable to serve in the armed forces. In 1941 these were replaced with the National Fire Service (NFS). Personnel records for the NFS and ARP have not survived but you can search our catalogue for surviving policy files and other records relating to central government oversight of the two services.

Air Raid Precautions (ARP) was established well before the war, but the number of wardens and their responsibilities increased from 1939 onwards. ARP wardens had various responsibilities including

• making sure no lights were visible during the ‘blackout’
• issuing gas masks and air raid shelters
• searching for survivors after bombing raids
• recording information about size and location of bombs and related damage

Bomb disposal crews were drawn from the Army (Royal Engineers) or the Royal Navy.

8. Records in other archives and online sources

Some county and local archives hold records created locally relating to the area, such as incident maps and registers or ARP wardens’ logs. There are also some useful online sources relating to Second World War bombing.

8.1 Online sources

Bomb Sight – includes digitised images of selected Bomb Census maps from HO 193

The West End at War – based mainly on sources from Westminster City Archives

Bath Blitz Memorial Project – an historical record of the bombing of Bath during the Second World War

8.2 County, metropolitan and local archives

To find records held in local archives, search our catalogue and restrict your search results to ‘Other archives only’ using the ‘Held by’ filter. Alternatively, find contact details for archives elsewhere using our Find an archive tool.

8.3 The London Archives

The London Archives holds the London County Council bomb damage maps and other records relating to bombing incidents in London.

8.4 Imperial War Museum

The Imperial War Museum has many personal reminiscences, both written and oral, from civilians and civil defence workers as well as photographs of air raid damage.

9. Further reading

You can search The National Archives’ library catalogue to see what is available to consult at Kew. Alternatively, visit The National Archives’ shop for a range of publications about bombing in the Second World War. Useful publications include:

Basil Collier, The defence of the United Kingdom (HMSO 1957)

Norman Longmate, The Doodlebugs: the Story of the Flying-Bombs (Hutchinson 1981)

Norman Longmate, Hitler’s Rockets: the Story of the V-2s (Hutchinson 1985)

Terence Henry O’Brien, Civil defence (HMSO 1955)

Bob Ogley, Doodlebugs and Rockets: the Battle of the Flying Bombs (Froglets 1992) – focuses on the V weapons that fell on South East London

Ann Saunders (ed), The London County Council Bomb Damage Maps 1939-1945 (London Topographical Society 2005) – includes a very useful introduction by Robin Woolven

Neil Wallington, Firemen at War, The Work of London’s Firefighters in the Second World War (Jeremy Mills 2007)

Peter Doyle, ARP and Civil Defence in the Second World War (Shire 2010)

Appendix 1: Civil defence regions

Use the below map to determine the relevant civil defence region: