On the outbreak of World War I the Territorial Force immediately mobilised for home defence, but shortly afterwards, its units were authorised to raise 2nd battalions formed from those men who had not volunteered for, or were not fit for, overseas service, together with new volunteers, while the 1st Line went overseas to supplement the Regulars. Early in 1915 the 2nd Line TF battalions were also raised to full strength to form new divisions, and began to form Reserve units to supply drafts. The remaining Home Service men were separated out in May 1915 to form brigades of Coast Defence Battalions.
9th Provisional Brigade
9th Provisional Brigade was formed in East Kent mainly from details of local units and infantry from Lancashire. It had the following composition:
9th Provisional Cyclist Company formed at Herne Bay on 8 September 1915 from two platoons of Home Service men drawn from 1/1st and 2/1st Kent Cyclist Battalions, the remainder from 1/6th Battalion Royal Sussex Regiment; it was temporarily attached to 42nd Provisional Battalion.
9th Provisional Battery and Ammunition Column Royal Field Artillery formed at Hastings on 9 September 1915 and shortly afterwards moved to Herne Bay; it was equipped with four French 90 mm field guns.
41st Provisional Battalion from home service details of the King's Own.
42nd Provisional Battalion formed on 1 September 1915 at Herne Bay from home service details of the 2/4th, 3/4th, 2/5th and 3/5th Battalions of the Loyal North Lancashire Regiment.
44th Provisional Battalion formed on 1 September 1915 from home service details of 7th, 8th and 9th Battalions of the King's Regiment and stationed in Ramsgate, Broadstairs and Sandwich.
45th Provisional Battalion formed from home service details of the Manchester Regiment.
9th Provisional Field AmbulanceRoyal Army Medical Corps, formed at Ramsgate on 19 September 1915 from the home service details of the 2/1st, 2/2nd and 2/3rd Home Counties Field Ambulances.
A number of men on the strength of these units were absent on civil employment such as munitions work. In the autumn of 1915 the brigade was under the command of 57th Division in Second Army of Central Force. By July 1916 the brigade was under the control of Southern Army of Home Forces, with its battalions billeted as follows:
Late in 1916 the War Office decided to form three new home-service divisions; 73rd was the last of these, assembling at Blackpool in November. The division was based on 9th Provisional Bde, which moved from Margate and provided four infantry battalions and many of the support units. In addition, 189th Brigade, left over after the earlier disbandment of 63rd Division, provided other components. Personnel to help form the other five artillery batteries were transferred from other home service divisions. The rest of the division was composed of new units. After assembling in Lancashire, 73rd Division moved in early January 1917 to join Southern Army of Home Forces, stationed in Essex and Hertfordshire, with the following composition: Divisions Headquarter in Chelmsford.
218th Brigade
218 Brigade was drawn from 9th Provisional Bde:
GOC: Brigadier-General H. Martin
Brigadier-General W.M. Withycombe Brigadier-General A. Martyn
41st Provisional Bn: became 12th Bn King's Own; disbanded 23 March 1918.
42nd Provisional Bn: became 14th Bn Loyals; the battalion was gradually drafted and disappeared by 17 December 1917.
44th Provisional Bn: 26th Bn King's; disbanded 29 March 1918.
267th Bn Training Reserve: joined by 23 July 1917, became 52nd Bn Leicestershire Regiment; transferred to 69th Division 17 January 1918.
* 9th Provisional Brigade Company ASC: became 829th Horse Transport Company ASC
* 830th, 831st and 832nd HT Companies ASC: newly formed
Training
The Military Service Act 1916swept away the Home/Foreign service distinction, and all TF soldiers became liable for overseas service, if medically fit. Henceforth part of the role of the Home Service divisions was physical conditioning to render men fit for drafting overseas, alongside units of the Training Reserve. 'Graduated Battalions' of the Training Reserve were organised in four companies according to age, from 18 to 19 years. Recruits progressed from one to another company after three months, so that every three months there was a company of trained 19-year-old men available for drafting overseas. In July 1917 it was decided that the Graduated Battalions could serve in a Home Defence role while completing their training. Between July and September 1917, four Graduated Battalions joined 73rd Division, and in October these were affiliated to line regiments and adopted territorial designations.
Disbandment
Towards the end of 1917 the War Office decided to break up the three home service divisions, and on 22 December 1917 the Commander-in-Chief, Home Forces, was ordered to break up the division as soon as possible. Three battalions left in January, the artillery was broken up in February, and the division ceased to exist on 8 April 1918. Only the divisional engineers remained, and on 22 June 1918 the HQ and field companies went to France for active service on the Western Front. The 73rd Division title has never been reactivated.
