Murray became Chief of the Imperial General Staff on 26 September 1915.[55] He was promoted to permanent lieutenant general on 28 October 1915.[56] After the war he wrote to Ian Hamilton, criticising Kitchener in harsh terms, writing that "He seldom told the absolute the truth and the whole truth" and that it was not until Kitchener left for his inspection of the Dardanelles that Murray was able to inform the Cabinet that volunteering had fallen far below the level needed to maintain a BEF of 70 divisions, requiring the introduction of conscription. The Cabinet insisted on proper General Staff papers being presented in Kitchener's absence. Murray wrote that "I have never in my forty years' service done better work than I did during the three months I was CIGS".