Turkey's entry into the war on 29 October 1914 immediately prompted Britain to open a new military front in the remote Ottoman province of Mesopotamia (present-day Iraq).

British and Indian troops, sent to the Persian Gulf in early November to protect British oil interests at Abadan, made rapid progress inland against weak Turkish resistance. In less than a month, they had occupied the towns of Basra and Kurna, capturing more than 1,000 Turkish prisoners and losing just 65 of their own men.

Despite the unforgiving climate, British forces continued to march steadily up the River Tigris in 1915. By 28 September, under the leadership of General Charles Townshend, they had taken the town of Kut-al-Amara just 120 miles south of Mesopotamia's major city, Baghdad. Scornful British estimates of Turkish fighting capabilities seemed to be amply borne out by events - witness, for example, the timorous surrender of 2,000 Turkish soldiers to a tiny British advance force in the garrison town of Amara in June 1915.

Despite the setback at Kut-al-Amara, the British position in Mesopotamia was far from hopeless. Indeed, with reinforced troop divisions and a new leader in General F S Maude, British and Indian forces again advanced rapidly up the Tigris in early 1917.

Kut-al-Amara was recaptured on 24 February, and Ctesiphon, where the previous British advance had been checked in November 1915, was taken soon afterwards. On 11 March, British troops finally entered Baghdad. The path was cleared for an advance into northern Mesopotamia, towards the heart of the Ottoman empire in Anatolia. When the war with Turkey ended on 30 October 1918, British forces in Mesopotamia had reached as far north as the oil-rich district of Mosul, which was captured on 3 November.

During the four years of fighting in the region, more than 31,000 officers and men from the British and Indian armies had died in combat or from disease.