The British Army introduced a new system of service-number allocations in 1920, assigning specific numerical ranges to individual regiments and corps. These allocations remained in use throughout the Second World War and can provide an important starting point for identifying a soldier's original regiment or branch of service.
The directory below provides a comprehensive reference to British Army service-number blocks from 1920 to 1945, arranged in ascending numerical order. Each allocation identifies the regiment or corps associated with that range, with links to our detailed WWII research guides for further investigation.
To use the directory, locate the range containing your soldier's service number and select the regiment or corps name to explore its history.
Notes
1. Numbers 558471–558761 were allocated to the Royal Armoured Corps within the wider Hussars numbering block (528001–721000). This exceptional allocation is distinct from the RAC's principal block of 7891869–8230000.
2. Disbanded in 1922 following the establishment of the Irish Free State. Their original service-number allocations are retained here for historical completeness, although these regiments did not serve during WWII.
3. Following the British Government's withdrawal of funding for the Channel Islands militias in 1928, their service-number allocations were discontinued in 1929. They are retained for historical completeness but were no longer active during WWII.
4. Disbanded in 1925 following the Lawrence Report on Army accountancy. Its personnel either returned to their former units or transferred to the Royal Army Pay Corps. The original number allocation (7733001–7757000) is retained for historical completeness.
5. Disbanded in 1922 as part of post-war reductions in military expenditure. Responsibility for machine-gun operations returned to individual infantry battalions and cavalry regiments, rather than remaining under a dedicated corps.
6. This dedicated allocation was reserved for Army Pay Corps personnel recruited in or from the Middle East, unlike the corps' predominantly British-based recruitment. It provides an unusual geographical clue within the Army's otherwise nationally organised pay service.
Understanding British Army Service Numbers
Under the numbering system introduced in 1920, British Army regiments and corps received designated blocks of service numbers from which new recruits were allocated their individual numbers. This replaced the earlier system in which different regiments could issue identical numbers.
Importantly, a service number usually identifies a soldier's original regiment or corps, not necessarily the unit in which they served during WWII. Soldiers generally retained their numbers when transferred between regiments, meaning a man serving in the Royal Artillery, for example, might carry a number originally allocated to an infantry regiment.
The ranges listed above represent official allocations rather than confirmation that every number was issued. Some blocks were discontinued, while others were reserved for particular recruitment categories or geographical areas.
Researching a WWII British Army Soldier
Identifying a soldier's original regiment or corps is often the first step in tracing their military service. Our free Army Service Explorer allows you to enter a British Army service number and identify its likely original allocation.
For more detailed research, select the relevant regiment or corps in the directory above to access our specialist WWII Technical Hubs. These guides explore regimental histories, wartime deployments, recruitment and the records available for tracing individual soldiers.
Remember that a service number provides a starting point, rather than a complete service history. Establishing where a soldier actually served may require additional military records.
Sources and Methodology
The principal source for this directory is War Office record series WO 212 – Army Number Blocks Allocation Registers, held by The National Archives. These records document the numerical ranges allocated to British Army regiments and corps under the numbering system introduced in 1920.
The directory presents these allocations in ascending numerical order, retaining exceptional and discontinued blocks for historical completeness. Where appropriate, regimental names have been standardised, and accompanying notes explain significant historical changes.
Each regiment or corps is linked to its corresponding WWII Technical Hub, providing further historical context and guidance for researching individual soldiers.