Selby was born in Lambeth, London, the son of Annie Elizabeth, a waitress, and Samuel Joseph Selby, a cab driver. After training at the Italia Conti Stage School, he made his adult stage debut in 1956. His theatre work includes the original production of Edward Bond's controversial play Saved at the Royal Court Theatre in 1965. He has appeared in many television programmes including a starring role in RAFNational Service comedy Get Some In!, and a recurring role in the BBCscience fiction television series Doctor Who as the intergalactic conman Sabalom Glitz. In 1965 he appeared as a convict under sentence of death in the BBC television dramaThree Clear Sundays, directed by Ken Loach. He had one of his earliest film acting roles in The Early Bird, Alfie, starring Academy award-winner Michael Caine, and his other film appearances include Press for Time, Poor Cow, Witchfinder General, Before Winter Comes, In Search of Gregory, Villain, Nobody Ordered Love, and . In 1971-2 he played magician's assistant Sam Maxstead in children's supernatural TV seriesAce of Wands and had a brief 1972 appearance as a jealous fiancé in Public Eye. He appeared in the 1970s series Callan. Other notable television appearances included The Avengers as a villainous car mechanic, Bless This House as a depressed burglar, and as Boozy in the all-star Eric Sykes comedy If You Go Down in the Woods Today. He appeared in three episodes of the critically acclaimed drama series Minder, twice playing Jack, the minder of gangster's wife Rose Mellors. In the early 1990s he played chauffeur to Adam Faith's character in the drama series Love Hurts; he also played Clive Mitchell in BBC's soap operaEastEnders in 2002. Selby appeared in the third episode of The Good Life, as a rag-and-bone man who sold the Goods an old wood stove and brought them a cat. In the United States, Selby had an uncredited role as a hood in the first Superman motion picture. Selby played Susan Harper's long-lost father Arthur in the BBC comedy My Family, in the episode "A Decent Proposal", first broadcast on 12 August 2011. In 2012 he appeared in the film Cockneys vs Zombies. He appeared in the television series New Tricks as Danny Paye, an East end loan shark in the 2009 episode Meat is Murder.
