Terrence Hardiman (born 6 April 1937) is an English actor. He is best known for playing The Demon Headmaster in the children's television series of the same name. Hardiman often plays authority figures, and has portrayed Nazi-era personnel (Secret Army, Colditz, Wish Me Luck and Enemy at the Door) and British officers (When the Boat Comes In). He has also played police inspectors (Prime Suspect, Juliet Bravo and Softly, Softly), doctors (Home to Roost, The Royal), barristers (Crown Court and The Brittas Empire), judges (The Bill and The Courtroom), a twelfth-century abbot, (Cadfael), and an evil headmaster (The Demon Headmaster). He also played Prime Minister Ramsay MacDonald, in Richard Attenborough's Gandhi.