road was required. Robertson's company was ordered to work on the road in November 1921. The road traversed some of the most remote, rugged and inhospitable terrain in India. The work was completed in October 1923, and was inspected by General Lord Rawlinson. For his work on the road, Robertson was mentioned in despatches twice more. The 3rd Field Company returned to Peshawar in October 1923, and Robertson was granted seven months' leave, commencing in April 1924. He returned to his family's home in Bayswater, where he bought a car, studied for the entrance examinations to the Staff College, Camberley, saw Edith Macindoe, whom he had met at a party in Scotland before his posting to India, and was best man at Jacob's wedding. He returned to Peshawar in December 1925, where he sat the staff college examinations in February 1925. Three weeks beforehand, he was hospitalised with a fever, and did not think he had performed well on the exams. Nonetheless, he was breveted as a major on 13 March 1925, and in April General Sir Claude Jacob, the acting Commander-in-Chief, India, (and Ian Jacob's father) asked Robertson to become his ADC. In June, Robertson received the news that he had been offered a place at Camberley. Robertson returned to England in December 1925, and commenced the two-year course at Camberley. He married Edith Macindoe on 4 August 1926. They had three children: Christine Veronica Helen, in 1927; William Ronald, in 1930; and Catherine Fiona, who was born in 1939. Staff college training was normally followed by a staff posting, and Robertson was posted to the Quartermaster General's Department at the War Office. After three months there, he was transferred to the Directorate of Military Operations and Intelligence (DMO&I), where he specialised in South America. In 1929, he visited six South American countries—Argentina, Bolivia, Chile, Ecuador, Peru and Uruguay—on a fact-finding tour. In his report, he noted that in four of these countries military training was being conducted by German military missions, and argued that military attachés should be posted to South America. The War Office and Foreign Office agreed, but HM Treasury did not, and the result was that the military attaché to the United States was also accredited to South American countries. Robertson was promoted to the substantive rank of major on 11 January 1930. In February 1932, he became a military advisor to the British delegation