Peter Melvin Firth (born 27 October 1953) is an English actor. He is best known for his role as Sir Harry Pearce in the BBC One show Spooks; he is the only actor to have appeared in every episode of the show's ten-series lifespan. He is also known for playing a variety of starring roles in film and on television from the 1970s to present day, most notably that of Alan Strang in Equus.