The Territorial Force (TF) was the volunteer reserve component of the British Army from 1908 to 1920, when it became the Territorial Army. The initial impetus for the creation of the Territorial Force came from Joseph Lyons, who also co-founded the eponymous chain of cafes known as the Lyons Corner Houses. The government legislation for the creation of the Territorial Force, the Territorial and Reserve Forces Act 1907 (7 Edw.7, c.9), was brought in by the Secretary of State for War at the time, Richard Burdon Haldane, which combined and re-organised the old Volunteer Army with the Yeomanry. The TF was formed on 1 April 1908. As part of the same process, remaining units of militia were renamed Special Reserve.
The TF was envisaged as a home defence force for service during wartime; units were liable to serve anywhere within the United Kingdom when the force was embodied, but could not be compelled to serve outside the country. However, any member or unit of the force could volunteer to be liable for overseas service - in 1910, when asked to nominate for Imperial Service overseas in the event of mobilisation, less than 10% of the Force chose to do so. Individual members could also choose to be liable to be called up for service within the United Kingdom even in situations when the force as a whole was not embodied.
On formation, the TF contained 14 infantry divisions, and 14 mounted yeomanry brigades. The individual units that made up each division or brigade were administered by County Associations, with the county's lord lieutenant as president. The other members of the association consisted of military members (chosen from the commanding officers of the units), representative members (nominated by the county councils and county boroughs in the lieutenancy county) and co-opted members (often retired military officers). Associations took over any property vested in the volunteers or yeomanry under their administration.
The basic building block was the yeomanry regiment or infantry battalion; these numbered 55 regiments of yeomanry, and 207 battalions of territorial infantry. In addition, there were 23 volunteer batteries of the Royal Garrison Artillery, 151 of the Royal Field Artillery, and 14 of the Royal Horse Artillery, as well as volunteer engineer, medical and supply companies. Each regiment or battalion had a regular army officer attached as full-time adjutant.
Every Territorial battalion of infantry was attached to a regular Army regiment; for example, the Royal Scots had two regular battalions, a reserve battalion, and seven Territorial battalions numbered the 4th through 10th.
The original divisions of the Territorial Army were:
- East Anglian Division (comprising units recruited in Bedfordshire, Cambridgeshire, Essex, Hertfordshire, Huntingdonshire, Norfolk, Northamptonshire and Suffolk)
- East Lancashire Division (Cumberland, part of Lancashire and Westmorland)
- Highland Division (Cities of Aberdeen and Dundee, counties of Aberdeenshire, Argyllshire, Banffshire, Buteshire, Caithness, Clackmannanshire, Dunbartonshire, Elginshire, Fife, Forfarshire, Inverness-shire, Kinross-shire, Nairnshire, Renfrewshire, Shetland, Stirlingshire, Sutherland and part of Lanarkshire)
- Home Counties Division (Middlesex, Kent, Surrey and Sussex) (broken up in India, December 1914)
- Lowland Division (Cities of Edinburgh and Glasgow, Counties of Berwickshire, Dumfriesshire, Haddingtonshire, Kirkcudbrightshire, Linlithgowshire, Midlothian, Peeblesshire, Selkirkshire, Wigtownshire and part of Lanarkshire)
- 1st London Division (City of London and part of the County of London)
- 2nd London Division (part of the County of London)
- North Midland Division (Derbyshire, Leicestershire, Lincolnshire, Nottinghamshire, Rutland and Staffordshire)
- Northumbrian Division (County Durham, Northumberland, East and North Ridings of Yorkshire)
- South Midland Division (Berkshire, Buckinghamshire, Gloucestershire, Oxfordshire and Warwickshire)
- West Lancashire Division (part of Lancashire)
- West Riding Division (West Riding of Yorkshire)
- Welsh Division (Wales, Cheshire, Herefordshire, Monmouthshire and Shropshire)
- Wessex Division (Cornwall, Devon, Dorset, Hampshire, Somerset, Wiltshire)
The original mounted brigades were:
- Eastern Mounted Brigade
- Highland Mounted Brigade
- London Mounted Brigade
- Lowland Mounted Brigade
- North Midland Mounted Brigade
- Nottinghamshire and Derbyshire Mounted Brigade
- South Eastern Mounted Brigade
- 1st South Midland Mounted Brigade
- 2nd South Midland Mounted Brigade
- South Wales Mounted Brigade
- 1st South Western Mounted Brigade
- 2nd South Western Mounted Brigade
- Welsh Border Mounted Brigade
- Yorkshire Mounted Brigade
In August 1914, after the outbreak of World War I, Territorial units were given the option of serving in France and, by 25 August, in excess of 70 battalions had volunteered. This question over the availability of Territorial formations for overseas service was one of Lord Kitchener's original motivations for raising the New Army separately.
A second line of Territorial units were raised by the respective County Associations in August and September 1914. As a result, the first-line battalions were renamed so that the 5th Battalion of the East Surrey Regiment became the 1/5th Battalion, and the second-line duplicate became the 2/5th Battalion. In many cases, a third-line battalion (the 3/5th) was formed after the first-line battalion was sent overseas, freeing up the second for foreign service; the third-line battalions were usually used for home defence or training; few saw action.
As the second line of battalions were organised for foreign service, a set of second-line divisions was formed, again prefixed with "2" to distinguish them - for instance, the second line 'Wessex Division' was originally called the '2nd Wessex Division'. However, many of these were quickly renumbered; divisions were assigned numbers in April 1915 and the 2nd Wessex became the 45th (2nd Wessex) Division.
The second line Territorial Force divisions were:
- 45th (2nd Wessex) Division
- 57th (2nd West Lancashire) Division
- 58th (2/1st London) Division
- 59th (2nd North Midland) Division
- 60th (2/2nd London) Division
- 61st (2nd South Midland) Division
- 62nd (2nd West Riding) Division
- 63rd (2nd Northumbrian) Division (broken up in July 1916)
- 64th (2nd Highland) Division (lost territorial association early 1918)
- 65th (2nd Lowland) Division (broken up 18 March 1918)
- 66th (2nd East Lancashire) Division
- 67th (2nd Home Counties) Division (lost territorial association early 1918)
- 68th (2nd Welsh) Division (lost territorial association early 1918)
- 69th (2nd East Anglian) Division (lost territorial association early 1918)
By the end of the war, 692 Territorial Force battalions had been raised. In total, 14 second line divisions were raised. No complete divisions of third line battalions were raised.
Also considered divisions of the Territorial Force were:
- 71st - 73rd divisions, which were formed late 1916 as Home Service divisions; all broken up early 1918
- 74th (Yeomanry) Division, formed early 1917 from dismounted Yeomanry
- 75th Division, formed early 1917 from various Territorial Force and Indian Army battalions
Territorial units initially saw service in Egypt, India and other Empire garrisons such as Gibraltar, thereby releasing regular units for service in France and enabling the formation of an additional five regular army divisions (for a total of eleven) by early 1915. The first Territorial division to join the fighting on the Western Front was the 46th (North Midland) Division in March 1915. The 42nd and 52nd divisions were sent to Gallipoli as reinforcements for the Helles front in May and June 1915.
As the war progressed, and casualties mounted, the distinctive character of Territorial units was diluted by the inclusion of conscript and New Army drafts. Following the Armistice, all units of the Territorial Force were gradually disembodied.
- Tony Mason and Eliza Ried, Sport and the Military: The British Armed Forces 1880–1960 (Cambridge: Cambridge University Press) p.39
- Richards, Walter, 1910. His Majesty's Territorial Army, Virtue.