Like Marshals of the RAF and Admirals of the Fleet, Field Marshals traditionally remain officers for life, though on half-pay when not in an appointment.[1][2] The rank has been used sporadically throughout its history and was vacant during parts of the 18th and 19th centuries (when all former holders of the rank were deceased). After the Second World War, it became standard practice to appoint the Chief of the Imperial General Staff (later renamed Chief of the General Staff) to the rank on his last day in the post. Army officers occupying the post of Chief of the Defence Staff, the professional head of all the British Armed Forces, were usually promoted to the rank upon their appointment.[3]