Haig, with the rank of lieutenant from 23 December 1915. He was mentioned in despatches on 1 January 1916. As part of the BEF staff, he was able to view the elaborate preparations for, and the early stages of, the execution of the Battle of the Somme. In July 1916, Robertson was posted to the headquarters of the XI Corps as a General Staff Officer Grade 3 (GSO3). The commander of XI Corps, Lieutenant-General Sir Richard Haking was a friend of his father's. He was promoted to captain on 16 January 1917, and accompanied his father on a tour of the Italian Front. The XI Corps sector of the Western Front was a quiet one at this time, but Robertson was mentioned in despatches on 15 May 1917, awarded the Order of the Crown of Romania with Swords on 21 June 1917, and the Military Cross in the 1918 New Year Honours. In response to the Italian defeat in the Battle of Caporetto, XI Corps was ordered to Italy on 18 November 1917, but by the time it arrived the front had settled down, and it saw little action. For his part, Robertson was made a cavalier of the Order of the Crown of Italy. When XI Corps returned to France in March 1918, Robertson was sent to Clare College, Cambridge, to attend a staff school. On completion of this training in July, he became brigade major of the 177th Brigade, part of the 59th (2nd North Midland) Division, which was assigned to XI Corps. As such, he participated in the Hundred Days Offensive. He was made a member of the Distinguished Service Order in the 1919 Birthday Honours, and was mentioned in despatches a third time on 5 July 1919. Between the wars After the war Robertson was posted back to Brompton Barracks to complete his interrupted engineering studies. In November 1920, he commenced a five-year secondment to the British Indian Army, on assignment to the Bengal Sappers and Miners, based at Roorkee, about north of Delhi. He assumed command of its 3rd Field Company, with Lieutenant Ian Jacob as his second in command in April 1921, and the company moved to Peshawar in the North-West Frontier Province. In the wake of the 1919–1920 Waziristan campaign, the Army had decided to establish a permanent garrison at Razmak, and to support the operations in Waziristan, construction of a new gravel