Riddington was born in Leicester.[1] Originally a stage actor, "truly dreadful" according to Riddington himself, he moved to a back stage role managing the Adelphi Theatre from 1950 and then directing the musical Rendezvous at the Comedy Theatre in 1952.[1] Later, he managed the London Palladium and Palace Theatres in London's West End.[2] After a period as a BBC television floor manager in the early 1970s, he became a producer. His first project as a producer to gain recognition was the 10 part serial adaptation of Anna Karenina (1977).[2]
For a time during the 1980s, he was the acting Head of Series & Serials in the BBC drama department, before returning to front-line producing work. Ending his period at the BBC at the age of 75, he and his wife Liz Riddington enjoyed twelve years of retirement before Ken moved to a London nursing home, where he was treated for dementia.[3]