The Special Reserve was established on 1 April 1908 with the function of maintaining a reservoir of manpower for the British Army and training replacement drafts in times of war.

Its formation was part of the military reforms implemented by Richard Haldane, the Secretary of State for War, which also created the Territorial Force.

In addition to providing replacements to the regular army, the Special Reserve was deployed on home defence duties guarding the coast and key installations during the First World War.

Originally recruited by various means of compulsion, the British Militia had become a voluntary institution by the late 19th century, and over 950,000 men had served in its ranks between 1882 and 1904.

[2] The Militia was, alongside the Yeomanry and the Volunteer Force, designed to supplement the regular army in defending the country against invasion and insurrection, and the three auxiliary institutions were not liable for service overseas.

[5][6] To make the small, professional British Army better able to cope with the increasing commitments of defending the empire, a series of reforms were begun by Edward Cardwell in 1871 and completed by Hugh Childers in 1881.

[5] The reorganisation did little to ease the army's manpower problems, and as early as 1879, during the Anglo-Zulu War, there were just 59 regular home battalions supporting 82 abroad.

[10]> Nearly 46,000 militiamen served in South Africa, another 74,000 were enlisted into the army, and five battalions were deployed as garrison troops on Malta, St. Helena and in Egypt.

[11][12] The experience in South Africa prompted further debate about the abilities of the army to intervene in a major foreign conflict and of the auxiliaries, which were perceived to have performed poorly during the war, to support it.

[b]These Extra Reserve Battalions, who were to deploy as a unit, for home or active service, were hindered as recruiting was generally poor.

[19] The reserve battalions were to be 550 strong, increasing to 1,500 on mobilisation with the arrival of Army Reservists not immediately required by the Expeditionary Force.

[19] The possibility of enlisting in the army under Regular terms of service were facilitated under paragraph 38, one precondition was that the recruit 'fulfils the necessary physical requirements.

A further 20,000 new recruits were enlisted, though 6,100 of them joined the army before completing their initial six months' training and some 2,000 were quickly rejected on medical grounds.

The problem was particularly acute in the officer corps; only 283 of the 18,000 men who had by 1912 graduated from the OTC had joined, leaving the Special Reserve some 50 per cent short in subalterns.

Faced with a shortfall in the Special Reserve of 13,000 in 1914, Haldane's successor, John Seely, identified the similar number of National Reservists who had agreed to be liable for service overseas as the means of bringing it up to establishment.

Special Reserve units experienced a high turnover of men in bringing their regular battalions up to strength and, once battle had been joined in France, replacing casualties.

[41] On the outbreak of war the three regiments of Special Reserve Horse were broken up to provide divisional cavalry squadrons for infantry divisions on the Western Front.

[45] These supplementary terms were rescinded on 7 November 1914 by Army Order 470, having served the purpose of facilitating the reenlistment of former soldiers, but it stressed that men could still enlist in the Special Reserve 'under conditions that existed before the war'.

[42] By September 1914, the Special Reserve had provided 35,000 replacements and was becoming so short of trained men that its ability to perform its home defence functions was in doubt.

[47] Field Marshal Sir John French, Commander-in-Chief, Home Forces, acknowledged the great difficulties the Special Reserve faced in "performing the double duty of training drafts...and defending our shores".

[60] The 3rd Battalion, Suffolk Regiment, suffered a number of fatalities in two air raids at Felixstowe during July 1917 – and most losses were due to sickness or training accidents.

The outbreak of the war saw a transformation of the Special Reserve, as its men were quickly posted to make good the losses suffered by the British Expeditionary Force.

In 1924 the Special Reserve/Militia's function was absorbed by the Supplementary Reserve, which was tasked with providing the regular army with specialist technical support in times of crisis.