Methodology

H0 203 files

The HO 203 files contain intelligence reports of enemy action on British domestic soil. They were prepared twice a day for the Home Security War Room, covering night-time attacks between 6pm and 6am and daytime attacks between 6am and 6pm.

The summaries were prepared by intelligence staff, who compiled reports received from the twelve civil defence regions and their regional intelligence officers. They provide an extraordinary daily account of bombing raids across the UK throughout the Second World War, and a running narrative of the home defence situation.

The reports are now bound in 16 volumes as The National Archives file series HO 203 (Ministry of Home Security: Daily Intelligence Reports). Routledge, Taylor & Francis Group have digitized these files alongside the records of ten other central British government departments in the War, State and Society digital resource.

How was the dataset created?

We have created a dataset of all German air attacks reported in the HO 203 files for which we were able to determine a location in England, Wales, Scotland, Northern Ireland, or the Channel Islands.

Generally, the intelligence reports record time and location of attack, type of bomb dropped, numbers of casualties, and damage to infrastructure. The reports are usually divided into four sections: first, a prose summary of enemy action; second, a list of all bombed locations, divided into the twelve civil defence regions; third, any updates on attacks that would fall under earlier reports; and fourth, a section on repairs.

From this information, we have extracted dates, locations, numbers of casualties, and any additional information. The dataset is intended to be faithful to the prose reports while maintaining a consistency in the formatting of the extracted data. The imperfections of the dataset – particularly the different levels of specificity in the entered data – reflect the complexity and frequent inconsistency of the information contained in the HO 203 intelligence reports.

For example, from the end of volume 14, the information about attacks becomes increasingly sparse, despite the heavy casualties caused by V rocket attacks. This seems to reflect the lessening institutional anxiety about the impact of bombing on the civilian population as the course of the war began to clearly shift in favor of Allied victory.

Also, the many hands behind the reports played a part in inconsistencies: the different intelligence officers display a variety of formatting preferences and approaches to the level of detail used to describe the attacks.

What locations were used?

The intelligence officials generally record locations on municipal level. That is, the reports show the town, village, or city attacked, but rarely provide specific addresses for dropped bombs. More specific locations are usually provided when bombs damage important factories, public buildings, or transport infrastructure.

However, London, as its own civil defence region, has attacks recorded by borough, and we have followed this practice in our dataset. The specificity of the attacks recorded on London reflects the civil defence structure of the region and provides more detail on the distribution and patterns of air raids on London.

If the location has been county-level or wider – for instance, "[s]ome bombs also fell in rural areas of Berkshire", or "some naval mines washed up between Essex and Newcastle" – we have considered the location too vague to include in the dataset.

After the end of October 1944, the prose reports stop recording the locations of V rocket attacks consistently. We have not been able to record air raids not attached to any location.

What times were used for attacks?

While we have not specified exact times of air raids, we have recorded whether an attack occurred at daytime or night-time. We have used one data row to represent all attacks occurring on a single location over a twelve-hour period. For example, if Camden was bombed twice in one night at 23:02 and 02:02, these two attacks are represented by one data point only.

How were casualties recorded?

We have used three columns for casualties, which correspond to the taxonomy of the intelligence officials behind the HO 203 files: injured, killed, and total casualties. When any of these numbers is not known or specified, we have made this clear. For example, when only number of total casualties is given, we have written the total casualty number under the relevant column and marked "Unspecified" under the "Injured" and "Killed" columns.

When the number of casualties has been updated in a later report, we have used the newer figure.

When vague descriptors for casualty numbers are used, such as "a number of casualties", "several casualties", "a few casualties", "some casualties", or "many casualties", we have quoted the text directly using double quotation marks to reflect the precise wording used to indicate estimated casualties.

When a range of casualties is given, for example, "Between 60 and 70 people were injured", we have used the higher figure (70) and written "Between 60 and 70 injured" under Additional Notes.

We have not assumed civilians who are trapped or missing after an attack to be casualties as, in later reports and addenda, these are frequently found alive and uninjured. We have recorded these cases instead under Additional Notes.

We have also indicated under Additional Notes those listed as casualties "due to shock" (whether fatal or non-fatal), as well as incidents when members of the bomb disposal service have been killed or injured while processing an unexploded bomb.

What counts as an air raid or attack?

An "attack" includes anything lethal deliberately dropped or fired from a German plane. These include: high explosive bombs, incendiary bombs, unexploded bombs, parachute mines, naval mines, magnetic mines, and machine gunfire.

In the case of the Channel Islands, we have also included troop landings. We have also recorded the many instances of long-range shelling, long-range explosive devices – including V rockets – gunfire, and cannon fire.

We have not included propaganda flyers dropped by German planes, plane crashes (whether German or British), or accidents resulting from British defence action.

Unexploded bombs and naval mines are frequently discovered at a later date than the day they were dropped; in these cases, we have marked "unexploded bomb" or "naval mine" under Additional Notes.

What file metadata is included?

The metadata information includes file series and volume numbers, numbers of all reports referring to an attack and hyperlinks to the first document referring to any particular air raid or bombing, which can be accessed by members of institutions and libraries that have purchased the digitized collections contained in War, State and Society.

We have included the numbers of all intelligence summary reports that document an attack and its aftermath. So, we have included not only the number of the first report discussing an attack, but also any subsequent reports that provide updates on casualty numbers, types of bombs, or damage to infrastructure. Users who have access to War, State and Society will be able to use these numbers to track the revisions, retellings, and reinterpretations of any attack in the HO 203 files.

References contained in the repairs section of the report, which tend to record details like opening of roads and or a train track resuming service, have not been included.

Unconfirmed Locations

We have identified a list of 190 unconfirmed locations across Great Britain that we are working to identify correctly. Updates to the data will be made periodically when confirmed.

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