Sir Thomas Leslie Rowan KCB CVO (22 February 1908 – 29 April 1972) was a British civil servant and industrialist. He served in the Colonial Office and HM Treasury, and was Principal Private Secretary to Winston Churchill and Clement Attlee, before joining the British Embassy in Washington, D.C., as economic minister. After some years heading the Overseas Finance Section of the Treasury, in 1966 he moved into the private sector as head of Vickers, and from 1971 until his sudden death was chairman of the British Council.