1915, the 2nd Mounted Division had to be reorganised. On 4 September 1915, the 1st Composite Mounted Brigade was formed from 1st (1st South Midland), 2nd (2nd South Midland) and 5th (Yeomanry) Mounted Brigades. Each dismounted brigade formed a battalion sized unit, hence the regiment was amalgamated with the Hertfordshire Yeomanry to form 5th Yeomanry Regiment. Western Frontier 5th Yeomanry Regiment left Suvla on 31 October 1915 for Mudros. It left Mudros on 27 November, arrived at Alexandria on 1 December and went to Mena Camp, Cairo. The brigade left the 2nd Mounted Division on 7 December, was reformed and remounted, and joined the Western Frontier Force. The Yeomanry Mounted Brigade was broken up by March 1916, and the regiment was attached to the 6th Mounted Brigade, still in the Western Frontier Force. The regiment was split up at the beginning of 1917: RHQ, C Squadron and the Machine Gun Section were on the Northern Section of the Suez Canal Defences A Squadron was assigned to the 53rd (Welsh) Division from 14 January to 14 February then with 74th (Yeomanry) Division from 5 April to 23 August B Squadron acted as the depot squadron at Zeitoun, Cairo from 17 January to 23 August Palestine The Westminster Dragoons now joined the Egyptian Expeditionary Force (EEF) for the Sinai and Palestine campaign. In August 1917, the regiment was concentrated and formed XX Corps Cavalry Regiment. The WDs were involved in fierce fighting, both mounted and dismounted. Early on 31 October the regiment took part in the attack on Beersheba. In the first phase it held a position on the right flank of XX Corps under shrapnel and machine gun fire. A and B Squadrons fired intermittent bursts of rifle and Hotchkiss machine gun fire, but expected a counter-attack. The infantry attacked at 12.15 in the second phase, and the Turks began retiring from their central position. At 14.00 the WD moved out in mounted pursuit but were held up after about a mile by heavy shrapnel and machine gun fire. At 16.30 the enemy retired. The WD's casualties amounted to one other rank (OR) and two horses killed, one officer, 16 ORs and several horses wounded; the engagement resulted in awards of one Military Cross (MC) and three Military Medal (MM) to members of the regiment. After the fall of Beersheba, the regiment was briefly split with C Sqn covering the advance