"[2] Born in Seven Kings, Ilford, Essex, Maddern attended Beal Grammar Boys school and afterwards joined the Merchant Navy at the age of 15 and served in the Second World War from 1943 until its end and was medically discharged in 1946.

[4] Appearing as Helicon in a production of Albert Camus' play Caligula (1964), Maddern was singled out for critical praise, and in My Darling Daisy (1970) portrayed the notorious Frank Harris.

[4] He also did two stints in the highly successful Agatha Christie play The Mousetrap - the longest-running production in London's West End.

[4] From 1950 to the early 1990s, Maddern appeared in films and TV series, often portraying military types, usually cast as sergeants or corporals, as well as privates, seaman or airmen, played either straight or comically,[5] one exception to this rule was when he portrayed a deformed hunchback, named Carl, in the horror film Blood of the Vampire (1958), another was when he played the lead role of a crippled bartender turned murderer in Street of Shadows in 1953.

[6] Among his many TV roles were Private Gross in Denis Cannan's Captain Carvallo, old Lampwick's son-in-law in The Dick Emery Show.,[7][8] and Tommy Finch, the British dad in Fair Exchange in 1962–63 on CBS network, one of the first hour-long situation comedies.