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.
Nick Carter (British Army officer) General Sir Nicholas Patrick "Nick" Carter, {'1': ", '2': ", '3': ", '4': "} (born 11 February 1959) is a senior British Army officer. He served as commanding officer of 2nd Battalion, Royal Green Jackets in which role he was deployed to Bosnia in 1998 and Kosovo in 1999. After service in Afghanistan, he took command of 20th Armoured Brigade in 2004 and commanded British forces in Basra. He was subsequently appointed General Officer Commanding 6th Division, which was deployed to Afghanistan with Carter as Commander ISAF Regional Command South, before he became Director-General Land Warfare. After that he became Deputy Commander Land Forces in which role he was the main architect of the Army 2020 concept. After a tour as Deputy Commander, International Security Assistance Force, he assumed the position of Commander Land Forces in November 2013. In September 2014, he became head of the British Army as Chief of the General Staff succeeding General Sir Peter Wall.