British army reserves and reservists

The word “reserve” appears a lot, either explicitly or disguised, in many military documents. This page should help you understand the different types of reserves and whether your soldier was among them at any time.

Reservists of the Grenadier Guards re-enlisting on the outbreak of War, queue for a medical inspection at Wellington Barracks, Westminster, London, 5 August 1914. Imperial War Museum image Q67397. If these men were reservesist they were not, technivally, re-enlisting but reporting back for full-time duty having received a mobilisation notice.
Imperial War Museum image Q67397. The caption reads, “Reservists of the Grenadier Guards re-enlisting on the outbreak of war, queue for a medical inspection at Wellington Barracks, Westminster, London, 5 August 1914”, but these men were not, technically, re-enlisting but reporting back for full-time duty having received a mobilisation notice.

The reserves of the regular army

In August 1914, in addition to the 247,500 currently-serving troops of the regular army, there were two forms of reserves for men below commissioned rank. The Army Reserve was 145,350 strong and the Special Reserve had another 64,000 men. See below also for the National Reserve.

1. Army Reserve

This was a pool of men who had already completed a term of service with the regular army. It was organised into three Sections:

Section A Reserve
For men who had completed their service in the regular army and who undertook to rejoin, if required, in an emergency that did not require general mobilisation. A man could serve no more than two years in Section A. Pay was 7 shillings a week in addition to the reservists earnings as a civilian. He had to attend twelve training days per year.

Section B Reserve
The most common form of army reserve service. For men who had completed their service in the regular army and were serving their normal period (typically of five years) on reserve. Section B reservists could only be called upon in the event of general mobilisation. Pay was 3 shillings and 6 pence a week. Training the reservists

Section D Reserve
For men who had completed their time in Section B Reserve. They could commit for four years and were placed in Section D Reserve. Men who had been discharged had up to six months to re-engage in this form of reserve. Terms, pay (at 6d per day, paid quarterly in arrears) and training was the same as Section B.

The Army Reservists were mobilised in early August 1914. Many went to fill up the ranks of the regular army units to their war establishment. All those surplus to the immediate needs of the regular army battalions were posted to the Special Reserve (see below). Thus the (usually) 3rd Battalion of each regiment was massively and very rapidly expanded. Very large numbers of men passed through the SR battalions before being posted to the regular units.

2. Special Reserve

This was a form of part-time soldiering, in some ways similar to the Territorial Force (see below). It was introduced as part of the  Haldane Reforms of 1908 and replaced the former Militia.

For details see The Special Reserve

See also: The Special Reserve (Category b)

3. Reserve of Officers

The army also maintained a list of officers on active reserve. Many were mobilised in 1914.

The reserves of the Territorial Force

The Territorial Force was created in 1908 as a form of part-time volunteer soldiering. Its original purpose was to provide a force for home defence and men were not obliged to serve overseas (until 1916). The troops undertook to serve full-time (to be “embodied”) in the event of general mobilisation.

1. Territorial Force Reserve

Most TF units struggled, until 1914, to attract sufficient men to fill their designed establishment and in consequence the reserves were well under strength. While theoretically the TF Reserve should have been one-third the size of the whole TF, by August 1914 it numbered only 2000 men. Detail of the TF Reserve

2. National Reserve

The National Reserve was a register maintained by Territorial Force County Associations. Registration was voluntary but complex rules of eligibility applied. Its strength as at 1 October 1913 was 215,000 of all ranks. Detail of the National Reserve

In October 1914 the National Reserve was formed into Protection Companies, which were attached to existing TF battalions, for the guarding of railways and other vulnerable points in Britain. That November, all Class I and II men were ordered to present themselves for enlistment. In March 1915 the Protection Companies were redesignated as Supernumerary Companies TF. In July 1915 there was a widescale trawl of these companies to identify men capable of marching 10 miles with a rifle and 150 rounds of ammunition. Those who were classified as medical Category A went to Service battalions, while Category C’s were posted to Provisional battalions. Cat B men were formed into the 18th-24th Battalions of the Rifle Brigade. These battalions were sent to Egypt and India at the end of 1915 to replace TF units committed to Gallipoli and Mesopotamia. The rump left in Britain eventually formed the 25th Battalion Rifle Brigade TF and served as a Garrison battalion at Falmouth. As for the Supernumerary Companies, they were eventually formed into the Royal Defence Corps.

New types of reserve created during the war

The Training Reserve

A considerable reorganisation of the reserve infantry battalions took place on 1 September 1916. Before this date, most of the infantry regiments contained one or more reserve battalions of the regular and new armies. Recruits would be posted to these battalions for basic training, before they were posted to an active service unit. With the introduction of conscription, the regimental system simply could not cope with numbers. A new structure was put into place: the Training Reserve.

Class W Reserve and its Territorial Force equivalent Class W(T)

Introduced in June 1916. See details at Classes W and W(T) Army Reserve

Classes T, P and P(T) Reserve

Introduced in October 1916. See details at Classes T and P Army Reserve

Authorisation was given in early December 1918 for all classes of the P and W Reserves (with the exception of conscientious objectors in the latter case) to be discharged forthwith, irrespective of their original terms of engagement.

Class Z Reserve

This was authorised by an Army Order of 3 December 1918. There were fears that Germany would not accept the terms of any peace treaty, and therefore the British Government decided it would be wise to be able to quickly recall trained men in the eventuality of the resumption of hostilities. Soldiers who were being demobilised, particularly those who had agreed to serve “for the duration”, were at first posted to Class Z. They returned to civilian life but with an obligation to return if called upon. The Z Reserve was abolished on 31 March 1920.

“The reserve”

The word “reserve” was used in many different ways by the British army of 1914-1918. The forces at home, whether they were of men going through basic training, manning the home defences or awaiting posting overseas, were “the reserve”. Units and formations overseas that were not actually at the fighting front were also “the reserve”. A battalion, on coming out of the line for rest, might say it was now in “brigade reserve”; a whole brigade, moving to the rear for training, might be in “Divisional reserve”; a Division of 20,000 men, also going further back, might be in “Corps reserve” and so on.

When an attack was made, a certain number of troops were held ready as a second wave, to exploit any gains made by the first troops to go in. These were also known as “reserves”. Commander-in-Chief Sir John French lost his job in late 1915 after controversy about his poor handling of the Divisions held in reserve at the Battle of Loos.