The British Army Service Number Tool is built using a combination of reconstructed regimental number ranges, wartime military records, and archival datasets.
British Army service numbers were issued in structured blocks rather than randomly. By analysing surviving records — particularly medal rolls, casualty databases, and surviving service files — historians have been able to reconstruct many of the numbering systems used by the Army during both world wars.
The tool brings together several of these historical sources to estimate likely regiments, enlistment periods, and wartime contexts for British Army service numbers.
Service records and the “Burnt Series”
One of the most important sources for reconstructing British Army service numbers is the surviving set of First World War service records held by The National Archives.
These records are commonly known as the “Burnt Series”, referring to files damaged during the bombing of London in the Second World War.
Today these surviving files are preserved within the archive series:
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WO 363 — Service Records (“Burnt Series”)
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WO 364 — Pension Records
Although incomplete, these records contain thousands of surviving service numbers linked to specific regiments and battalions. They remain one of the key sources used by historians studying First World War enlistment patterns.
Medal Rolls and Medal Index Cards
Another major source for reconstructing British Army numbering systems is the medal documentation created at the end of the First World War.
Two particularly important datasets survive:
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WO 372 — Medal Index Cards
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WO 329 — Medal Rolls
Medal Index Cards record each soldier who qualified for campaign medals such as the British War Medal or Victory Medal, along with their regiment and service number.
The Medal Rolls provide even more detailed information, often confirming the battalion in which a soldier served. Together these records provide one of the largest surviving datasets linking service numbers to specific units.
Casualty records
Casualty databases provide another valuable source of service number data.
The Commonwealth War Graves Commission database records the details of more than a million Commonwealth servicemen who died during the two world wars. These records frequently include both service numbers and regiments.
By analysing large numbers of casualty entries, historians can identify patterns in how service numbers were issued within different regiments.
Regimental research and reconstructed number ranges
Over the past two decades, several researchers have undertaken detailed studies of British Army service numbers.
One of the most widely used resources is the research compiled by Paul Nixon, which documents the early numbering systems across many infantry regiments during the First World War.
By comparing these reconstructed ranges with surviving archival records, it becomes possible to estimate:
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likely regiments of enlistment
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approximate recruitment periods
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battalion ranges within regiments
These reconstructed datasets form an important foundation for the British Army Service Number Tool.
Second World War number block allocations
By the outbreak of the Second World War, the British Army had introduced a more centralised system for issuing service numbers. Instead of individual regiments issuing their own numbers, the War Office allocated large blocks of numbers to specific regiments and corps.
The primary source for reconstructing these allocations is the archive series WO 212 – Army Number Block Allocation Registers held at The National Archives. These registers record how service number ranges were distributed across different regiments and branches of the army.
For example, the number block 5485001–5562000 was allocated to the Hampshire Regiment. A soldier whose service number falls within this range therefore most likely enlisted into that regiment before later postings or transfers.
These number block registers form the core dataset used by the British Army Service Number Tool to interpret Second World War service numbers.
Use the Service Number Tool
By entering a WWI or WWII service number, the tool can help estimate:
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likely corps or regiment
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approximate recruitment period
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the wider context of a soldier’s service
- the potential battles fought in
How the British Army Service Number Tool uses these sources
The British Army Service Number Tool combines several layers of historical evidence:
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reconstructed regimental number ranges
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archival military records
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casualty databases
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regimental research datasets
By comparing a service number with these sources, the tool estimates the most likely historical context for that number.
Although service numbers alone cannot confirm a soldier’s full wartime career, they often provide a valuable starting point for further research.