posted to the 7th Infantry Brigade as its brigade major. In 1931 he became brigade major of the 1st Cavalry Brigade in Queensland. He returned to Sydney in February 1934 as General Staff Officer (Grade 2) at the 2nd District Base. In June 1934, he was appointed Director of Military Art at the Royal Military College, which had been transferred to Victoria Barracks, Sydney, as a cost-cutting measure during the Great Depression. It returned to Canberra in 1937, and Robertson returned with it. Robertson was finally breveted as a lieutenant colonel in June 1936. The rank became substantive in July 1937. Like other regular officers, Robertson was opposed to the "Singapore strategy", and therefore to the defence policy of the government of the day, and said so publicly in the British Army Quarterly. Robertson argued for a local defence of Australia by land and air units. The naval theorist, Admiral Sir Herbert Richmond, responding to Robertson's arguments in an editorial, pointed out that local defence would fragment the British Empire's defence effort and could not secure the sea lanes. However, in view of the weakness of the Royal Navy, Richmond was forced to concede that Robertson's approach was not unreasonable. Second World War Libya In March 1939, Robertson was appointed commander of the 7th Military District, which encompassed the Northern Territory. It was his first command since the First World War. He was promoted to the temporary rank of colonel in August 1939, and this became substantive in November. The job involved cooperation with the Royal Australian Navy and Royal Australian Air Force, and the administration of a company of regular soldiers known as the Darwin Mobile Force. After the Second World War began in September 1939, Robertson became responsible for supplying the 7th Military District's quota of volunteers for the Second Australian Imperial Force (AIF). A strike on the waterfront saw Robertson committing troops to help unload cargo. On 4 April 1940, Robertson joined the Second AIF himself, with the rank of brigadier, and was allocated the AIF service number VX20321. He was appointed to command the 19th Infantry Brigade, which was then being formed from units made surplus by the reduction of the 6th Division from 12 infantry battalions to nine. All three of its battalions, the 2/4th, 2/8th and 2/11th Infantry Battalions, were initially commanded by over-age officers, but the commander of the 2/4th was replaced by