Derek Newark (8 June 1933 – 11 August 1998) was an English actor in television, film and theatre.
He appeared in a large number of film and television roles, including The Baron (1967), The Avengers (three episodes in the 1960s), Z-Cars (six episodes between 1969 and 1972), Barlow in the regular role of Det. Insp. Tucker (1974–1975) and various other minor roles. He appeared in episodes two to four of the first Doctor Who story An Unearthly Child in 1963. Later he appeared opposite Jon Pertwee in the 1970 story Inferno. Newark also played the role of Spooner, an ill-tempered former Red Devil turned professional wrestler in the series Rising Damp.
In the 1970s he became more involved in the theatre, spending nearly a decade at the Royal National Theatre. While there he was part of the company that opened the current home and was a cornerstone of the residential company that worked in the smaller Cottesloe Theatre under Bill Bryden's direction. His most important roles there were Bottom in A Midsummer Night's Dream and the world premiere of David Mamet's Glengarry Glen Ross where he played Shelley Levene (a role later played on screen by Jack Lemmon) and Malcolm in Alan Ayckbourn's Bedroom Farce, which also played in the West End and on Broadway. He also a created the role of Roote in Harold Pinter's play The Hothouse which premiered in 1980 in a production directed by the playwright. Pinter went on to play the part himself in a later revival. He starred in the second series of Juliet Bravo as Councillor Jack Winterbottom. In 1982, Newark played Martin Bormann in the TV series Inside the Third Reich.
Derek Newark died of a heart attack, brought on by liver failure after years of alcoholism, on 11 August 1998 in West London.