William Russell Enoch (19 November 1924 – 3 June 2024) was an English actor who performed as both Russell Enoch and William Russell. His career on stage and screen spanned over seven decades and he first achieved prominence in the title role of the television series The Adventures of Sir Lancelot (1956–1957). In 1963, he was in the original lead cast of BBC1's Doctor Who, playing the role of schoolteacher Ian Chesterton from the show's first episode until 1965.

Russell's film roles include parts in The Man Who Never Was (1956), The Great Escape (1963) and Superman (1978). On television, he appeared as Ted Sullivan in Coronation Street in 1992. In his later years, he continued his association with Doctor Who and returned as Ian for a 2022 cameo in "The Power of the Doctor", 57 years after the character left, which won him a Guinness World Record for the longest gap between TV appearances.