Sir Richard William Barnes Clarke, KCB, OBE (commonly known as Otto Clarke) (13 August 1910 – 21 June 1975) was a British civil servant.
Clarke was educated at Christ's Hospital, London and Clare College, Cambridge, where he was sixth wrangler in 1931. He sat the examinations of the Royal Statistical Society in 1932 and was awarded their Frances Wood Prize.
Clarke worked for the British Electrical and Allied Manufacturers' Association, 1932–33. He was then on the staff of the Financial News (later taken over by the Financial Times) until 1939 and devised the Ordinary Share Index, now the Financial Times Ordinary Share Index.
During World War II he served in the Ministries of Information, Economic Warfare, and Supply and Production, and with the Combined Production and Resources Board in Washington, 1942–43.
He joined the Treasury in 1945 and was its Second Permanent Secretary, 1962–66. He was then Permanent Secretary at the Ministry of Aviation in 1966, then at the Ministry of Technology until 1970, retiring from the Civil Service in 1971. From 1973, he was a Vice-President of the Royal Institution.
Richard Clarke was given the honours of OBE in 1944, Companion of the Bath in 1951, and Knight Commander of the Bath in 1964.