In 1920, the army introduced a new system of issuing numbers to its men and women. Each soldier would have a unique number, an army number. Before that, each regiment (and in some cases, the units in a regiment) issued its own numbers. This meant that when a man changed regiments, he usually had to change number. Some of those regimental numbering schemes included letter prefixes. These can offer useful clues.
Tip: prefix? what prefix?
Don’t worry if your man did not have a number prefix: most did not. But mine’s not there! The list of prefixes below is almost certainly incomplete and is offered as general guidance only.
| Prefix | Regiments known to have used this prefix | Notes |
| A | Royal Sussex Regiment, King’s Royal Rifle Corps | |
| A | Army Service Corps | Expeditionary Force Canteens Section A |
| AHT or A(HT) | Army Service Corps | Horsed Transport Special Reserve |
| B | Rifle Brigade | |
| B | Royal Fusiliers | Bankers Battalion |
| BHT or B(HT) | Army Service Corps | Horsed Transport Special Reserve |
| C | Royal Irish Rifles | |
| C | King’s Royal Rifle Corps | 16th Bn (Church Lads Brigade) |
| CA | Army Service Corps | |
| CMT or C(MT) | Army Service Corps | Mechanical Transport Special Reserve |
| D | Honourable Artillery Company, Dragoons, Dragoon Guards, King Edward’s Horse, Sussex Yeomanry, Hertfordshire Yeomanry | |
| DM2 | Army Service Corps | Mechanical Transport Learner |
| E | Royal Fusiliers | Used for 17th (Empire) Bn |
| E | Army Service Corps | Forage |
| F | Royal Fusiliers, Middlesex Regiment | ‘Football’ battalions |
| F | Army Service Corps | Forage (not paid from Army Funds) |
| G | Many regiments | General service |
| GS | Many regiments | General service |
| H | Hussars regiments, North Irish Horse, Army Cyclist Corps | |
| H | Army Service Corps | |
| J | Royal Fusiliers, Middlesex Regiment | Middlesex: this prefix was used for the 38th, 39th and 40th Bns (Jewish) |
| K | Royal Fusiliers | Kensington Battalion |
| L | Lancers regiments | |
| L | Royal Field Artillery | Local enlistment |
| L | Many infantry regiments | |
| M | Honourable Artillery Company | |
| M | Army Service Corps | Mechanical Transport |
| M1 | Army Service Corps | Mechanical Transport |
| M2 | Army Service Corps | Mechanical Transport |
| MS | Army Service Corps | Mechanical Special |
| NAC | Army Service Corps | |
| NCB | Northern Cyclist Battalion | |
| O | Rifle Brigade | |
| O | Army Ordnance Corps | |
| P | Rifle Brigade | |
| P | Military Foot Police and Military Mounted Police | |
| PET | Army Service Corps | Petroleum Department |
| PS | Royal Fusiliers, Middlesex Regiment | Public Schools Battalions |
| PW | Middlesex Regiment | Public Works Battalion |
| R | Many infantry regiments | |
| R | Army Veterinary Corps | |
| R4 | Army Service Corps | Remounts |
| RS | Army Service Corps | Remounts Special |
| RTS | Army Service Corps | Remounts Special |
| RX4 | Army Service Corps | Remounts |
| S | Many infantry regiments | General service |
| S | Army Service Corps | Supply. Often accompanied with a number, denoting recruitment into the appropriately numbered Kitchener (New) Army |
| SD | Royal Sussex Regiment | South Downs Battalions |
| SE | Army Veterinary Corps | Special enlistment (General service) |
| SPTS | Royal Fusiliers | Sportsmen’s Battalion |
| SR | Many regiments | |
| SS | Royal Field Artillery | Shoeing Smith |
| SS | Army Service Corps | Supply Special |
| STK | Royal Fusiliers | Stockbroker’s Battalion |
| T | Many regiments | Territorial |
| T | Army Service Corps | Horsed Transport. Often accompanied with a number, denoting recruitment into the appropriately numbered Kitchener (New) Army |
| TF | Many regiments | Territorial |
| TISR | Army Service Corps | |
| TR | Training Reserve | |
| TS | Army Service Corps | Transport Special |
| TSC | Army Service Corps | |
| TT | Army Veterinary Corps | Territorial |
| W | Royal Field Artillery | Welsh |
| W | Cheshire Regiment | Wirral |
| W | Military Provost Staff Corps | |
| WE | Royal Army Medical Corps | |
| WT4 | Army Service Corps | Welsh Horsed Transport |
| Y | King’s Royal Rifle Corps | Special Reserve |
| Z | Rifle Brigade | Special Reserve |
Army Service Corps
CAN or CANTEEN
The man had been enlisted into the ASC for work in the Expeditionary Force Canteens. This prefix is varied in the way it is presented and can sometimes be seen with an added letter: A: accountants and clerks; E: employees and workmen. Rather confusingly this was later altered to A: employees and workmen and B: accountants and clerks.
E
The man had been enlisted into the Forage section of the ASC.
F
The man had been enlisted for work with the Forage section of the ASC but was not paid by the army.
M
The man served in the Mechanical Transport section of the ASC. The prefixes C(MT), M1(SR), M2(SR), M1, M2, DM2 and MS are also often seen. The C(MT) tells us that the mad had enlisted into the ASC’s Special Reserve (many of these men had been chauffeurs or motorised van drivers before joining). M1 and M2(SR) had also enlisted on Special Reserve terms but for service with a unit of the New Armies. The precise definition of M1 and M2 is not clear but appers to be that the man had enlisted into the New Armies (it does not imply that he joined before conscription). DM2 appears to have been applied to learner drivers (although many M1 and M2 men were also learners when they enlisted) until it was discontinued in November 1916. MS means that the man was specially enlisted for his trade: in other words, he came from civilian employment in a trade that was of direct value to work in the Mechanical Transport section: he may have been a motor engineer or tyre fitter, for example. If the man has an EM prefix then he was re-enlisted after the war.
PET
This man had been enlisted for work in petroleum supply.
R
The man served in the Remounts section of the ASC. The prefixes RS, R/TS, R4 and RX4 are also often seen. The “S” means that the man was specially enlisted for his trade: in other words, he came from civilian employment in a trade that was of direct value to work in the Remounts. The “R/TS” implies that the man was specially enlisted for work in the Remounts and/or Horse Transport. R4 and RX4 are less clear but may relate to the compulsory transfer in 1916 of men who were serving in ASC units of the Territorial Force on to regular army terms. If the man has an ER prefix then he was re-enlisted after the war.
S
The man served in the Supply section of the ASC. The prefixes SS and S1 to S4 are also often seen. SS means that the man was specially enlisted for his trade: in other words, he came from civilian employment in a trade that was of direct value to work in the Supply section: he may have been a clerk, butcher or baker, for example. S1 to S4 mean that the man was enlisted into the first to fourth New Army depending on the number after the S. If the man has an ES prefix then he was re-enlisted after the war.
T
The man served in the Horse Transport section of the ASC. The prefixes A(HT), B(HT), T1(SR), T2(SR), TS and T1 to T4 are also often seen. A(HT) and B(HT) mean that the mad had enlisted into the ASC’s Special Reserve. T1 and T2(SR) had also enlisted on Special Reserve terms but for service with a unit of the New Armies. TS means that the man was specially enlisted for his trade: in other words, he came from civilian employment in a trade that was of direct value to work in the Horse Transport: he may have been a shoesmith, for example. T1 to T4 mean that the man was enlisted into the first to fourth New Army depending on the number after the T. T4 was also used for men affected by the compulsory transfer in 1916 of men who were serving in ASC units of the Territorial Force on to regular army terms. If the man has an ET prefix then he was re-enlisted after the war.
Royal Naval Volunteer Reserve prefixes
This may seem a little odd to include in a site about the British Army, but it relates to the fact that many men would fought at Gallipoli, France and Flanders with the Royal Naval Division (later known as the 63rd (Royal Naval) Division) enrolled into the RNVR.
Divisions
The RNVR was subdivided into six “divisions” for pay and administration purposes. (This is not the same use of the word “division” when it meant a formation of the British Army). The divisions gave a letter prefix to the man’s number. Each division had its own sequence of numbering its recruits. Thus:
- Bristol Division: prefix “B”;
- Clyde Division: “C”;
- London Division: “L”;
- Mersey Division: “M”;
- Sussex Division: “S”;
- Tyne Division: “T”.
During the Great War, two more “War Fleet Divisions” were added:
- Crystal Palace Division: “P”;
- Wales Division: “W”.
War Fleet recruits
Men who enrolled for war service were also given a “Z” prefix. Thus a man enrolled for war service in the Bristol Division would be prefixed “BZ”.
Kitchener’s Army transferees
A number of men were transferred from the army (new recruits who had joined Kitchener’s Army) in 1914. They were given the additional prefix “K”.
Others
A number of other letter prefixes were used during the war but the above description covers most instances.