One of Turner's most recognisable roles was that of Roderick Spode (6 episodes, 1991–1993) in the ITV television series Jeeves and Wooster, based on the P. G. Wodehouse novels.
He had performed the same role earlier in his career at Her Majesty's Theatre, London in Andrew Lloyd Webber's musical flop Jeeves.
He also portrayed Charlemagne in the original West End cast of Pippin at His Majesty's Theatre.
In a career that lasted more than 40 years, he also appeared in 36 episodes of Knight Errant Limited as Adam Knight (1959–1960), as well as in episodes of Z-Cars (1967), The Saint (1968), The Champions (1968), Fall of Eagles (1974), the TV mini series Lorna Doone (1976), Heartbeat (1992), The Adventures of Young Indiana Jones (1999) and The Bill (2000).
Film roles include John in Behemoth the Sea Monster (1959), Lieutenant Pattinson in Petticoat Pirates (1961), Sir Richard Fordyke in The Black Torment (1964), Joab in Captain Nemo and the Underwater City (1969), The Major-domo in The Slipper and the Rose (1976), the Afrikaner Minister in The Power of One (1992), Rasputin: Dark Servant of Destiny (1996) and Lord Lot in Merlin (1998).