[2] He graduated from the Royal Academy of Dramatic Art in 1961 and appeared in their production of The Doctor and The Devils by Dylan Thomas.

Alderton first became familiar to television viewers in 1962, when he played Dr Moone in the ITV soap opera Emergency Ward 10.

[3] In 1972, he appeared with Hannah Gordon in the BBC comedy series My Wife Next Door which ran for 13 episodes, and for which he won a Jacob's Award in 1975.

He then transferred to another top-rated ITV series when he played Thomas Watkins, the chauffeur, in Upstairs, Downstairs, opposite his wife, Pauline Collins.

After a period in repertory, he made his first London appearance at the Mermaid, November 1965, as Harold Crompton in Spring and Port Wine, later transferring with the production to the Apollo.

Alderton played opposite his wife Pauline in Mrs Caldicot's Cabbage War in 2002 and made something of a comeback in the 2003 film, Calendar Girls.

Also in 2004, Alderton starred in the first series of ITV 1's Doc Martin in an episode entitled "Of All The Harbours in All The Towns" as sailor John Slater, a friend and former lover of Aunt Joan.