William Russell Enoch is an English actor. He achieved prominence when he took the title role in the ITV television series The Adventures of Sir Lancelot (1956–1957). In 1963, he became part of the original lead cast of BBC1's Doctor Who, playing the role of schoolteacher Ian Chesterton opposite William Hartnell from the show's first episode until 1965.

The Adventures of Sir Lancelot is a British television series first broadcast in 1956, produced by Sapphire Films for ITC Entertainment and screened on the ITV network. The series starred William Russell as the eponymous Sir Lancelot, a Knight of the Round Table in the time of King Arthur at Camelot.