Muriel was born in Bishop Middleham, near Sedgefield, Co Durham. On leaving school, she worked briefly as a librarian. She attended art college, before deciding to embark on a career as an actress. She joined a repertory theatre in Henley-on-Thames, where her uncle was directing. She subsequently performed at the Gateway Theatre, London and the Theatre Royal in Chatham. Trying to get into the film industry, she did modelling for advertising agencies, including promoting products such as toothpaste. She also studied to be a dental nurse and used her artistic talents to paint glassware. Starting out as an actress, she starred with Rex Harrison and Kay Kendall in The Constant Husband (1955) and also featured in The Story of Gilbert and Sullivan (1953) in a segment featuring The Mikado.
Muriel had a screen test for a BBC TV announcer position on 24th June 1952. In 1955, as the first ITV company (Associated-Rediffusion) was gearing up to launch, she intended to attend an actors’ audition at the company, but mistakenly went to an audition for announcers instead. Nevertheless, Young was instantly hired and announced for Associated-Rediffusion on 22nd September 1955, the opening night of commercial television in the UK. She worked as a presenter and interviewer for regional programmes on Granada Television and Southern Television, and as a disc jockey on Radio Luxembourg. She was cast alongside Peter Sellers in the movie I’m All Right Jack (1959) as an announcer, without the director knowing that it was in fact her real-life job.
However, her career could have easily taken a different route. Just before joining ITV, she had been on stage touring with Eamonn Andrews, in a game show called Double or Drop. Shortly after signing her ITV contract, he told her that he had sold the idea to the BBC. It was later used as part of the children’s show Crackerjack!