William Thomas (born 1946) played Martin in the Doctor Who television story Remembrance of the Daleks and Cleaver in the Doctor Who television story Boom Town. He also played Geraint Cooper in series 2 and 4 of Torchwood.
He is the first actor to appear in both the classic and revived series of Doctor Who. Furthermore, he is the only actor to appear in both of those series and Torchwood.