The Chiefs of Staff Committee is composed of the most senior military personnel in the British Armed Forces. It was initially established as a sub-committee of the Committee of Imperial Defence in 1923. It remained as such until the abolition of the CID upon the outbreak of World War II in 1939. The initial composition of the committee was the professional heads of the three services, the First Sea Lord, the Chief of the Imperial General Staff and the Chief of the Air Staff. Each service head took turns being chairman of the committee. During World War II the committee was a sub-committee of the War Cabinet, and in addition to the three service chiefs, it had an additional member, in the person of General Sir Hastings Ismay, who acted as its secretary. Subcommittees of the Committee were also formed, including the Joint Planning Staff and Joint Intelligence Committee. The Chiefs of Staff committee was responsible for the overall conduct of the British military part of the war effort. When matters required joint Anglo-American decision, the Chiefs of Staff Committee members formed part of the Combined Chiefs of Staff, meeting in concert with their American counterparts, the Joint Chiefs of Staff. The Combined Chiefs of Staff were based in Washington, so for most of the time the Chiefs of Staff were represented at meetings by the British Joint Staff Mission. Following WWII, the Chiefs of Staff Committee was transferred to the Ministry of Defence. Further change came in 1956, with the creation of the post of Chief of the Defence Staff. The CDS became chairman of the committee and professional head of the British military. In 1964, the post of Chief of the Imperial General Staff was discontinued and the Army was thereafter represented by the Chief of the General Staff. Since then, the only major change has been the appointment of the Vice-Chief of the Defence Staff to act as a deputy to the CDS.
