At the outbreak of war the Territorial battalion of the Dorset Regiment, the 4th, were at their annual summer camp. Mobilised at once, the Battalion was soon divided to form the 1/4th and the 2/4th. Men who volunteered to serve overseas joined the 1/4th and sailed on 9th October for India, where they relieved a Regular Army battalion to fight in France or Mesopotamia. They thus reinforced the Regiment’s motto Primus in Indis (which dated from 1754) by becoming the first Territorials to arrivon the sub-continent.
After service and rigorous training in India the 1/4th landed at Basra in late February 1916 as part of 15th Indian Division. A strenuous twelve-day desert march took them to Nasiriyeh, which became their base. In late September 1917 they played a decisive part in the battle of Ramadi on the Euphrates, capturing with two Gurkha battalions the ridge that dominated the Turkish position. The 1/4th‘s part in this success was specifically mentioned in the official despatch. Six months later, on 23rd March 1918, the Dorsets played a leading part in capturing Khan Baghdadi, where 5,000 Turks were taken prisoner. At the end of the war a draft from the 1/4th was sent to Salonika while the rest of the Battalion returned to England for demobilisation.
In early January 1915 the 2/4th Dorsets followed the 1/4th to India, where they remained until they were sent to Egypt in August 1917. The rest of their war would be spent with the 75th Division in Egypt and Palestine. Their first action was in the Third Battle of Gaza, when in late October and early November they held the front line for a fortnight during which they repulsed three Turkish attacks. They fought at Nebi Samwil (the Tomb of Samuel) in late November before Allenby’s capture of Jerusalem on 9th December 1917. In 1918 they fought at Deir Ballut on 12th March, capturing and holding their objectives in the face of fierce counter-attacks. In April near Berukin the 2/4th took Three Bushes Hill and again held it despite savage attacks by the Turks. During this action the Battalion spent 96 hours in almost continuous marching an fighting, losing some 90 officers and men killed, wounded or captured. In August, before the decisive Battle of Megiddo, the 2/4th were disbanded and the troops dispersed to provide reinforcements to other units.
When the 2/4th Dorsets left for India the remaining Territorials were renamed the 3/4th (Home Service) Battalion. Throughout the war they trained recruits and sent drafts to the Regiment’s other battalions serving overseas. When the war ended the 3/4th were performing garrison duties in Londonderry.