High Quality Content by WIKIPEDIA articles! No. 600 (City of London) Squadron RAuxAF is a squadron of the RAF Reserves. It was formed in 1925 and operated as a night fighter squadron during the Second World War with great distinction. After the war, 600 Squadron went on to operate jet fighters until 1957. Reactivated in 1999, 600 Squadron is the only RAF Reserve unit within the M25. It is a Headquarters Support Squadron and provides trained part-time reservists to support RAF operations around the world.