He is best remembered for his namesake role from 1973 to 1977 as the comically ferocious prison warder, Mr Mackay, in the British sitcom Porridge alongside the comedian and comedy actor Ronnie Barker [REF].
He was cast as misguided scientist Doctor John Quinn in the 1970 Doctor Who story Doctor Who and the Silurians and was later seriously considered by producer Barry Letts to play the Fourth Doctor when Jon Pertwee announced he was leaving the role in 1973 [REF].