Since when has the rank of James Cassels been at its current level in the British Army?
James Cassels (British Army officer) Field Marshal Sir Archibald James Halkett Cassels, {'1': ", '2': ", '3': ", '4': "} (28 February 1907 – 13 December 1996) was a senior British Army officer who served as Chief of the General Staff, the professional head of the British Army, from 1965 to 1968. As a young man he was a first-class cricket player, initially playing in India for the Europeans against the Hindus in the Lahore Tournament and going on to play for a Punjab Governor's XI against Northern India team and for a Viceroy's XI against the Roshanara Club. He later played for the British Army cricket team against the RAF at The Oval and then played for the Egyptian national side against HM Martineau's XI in Alexandria.
John Whiteley (British Army officer) General Sir John Francis Martin Whiteley (7 June 1896 – 20 May 1970) was a senior British Army officer who became Deputy Chief of the Imperial General Staff (DCIGS). A career soldier, Whiteley was commissioned in 1915 into the Royal Engineers from the Royal Military Academy, Woolwich. During World War I he served in Salonika and the Middle East.