It might not have happened for Jimmy Young at the BBC. After six years in the RAF from 1939 (he was a PT instructor, but also immersed himself in ENSA) he found an agent in Lilian Aza, who looked after Gracie Fields. She sent him to audition at the BBC; but he got a letter of rejection.
He carried on as a clerk at the Ministry of Education, and got a gig singing and playing the piano in a sports club in Thames Ditton. There he caught the ear of BBC producer George Innes. And, lo, on August 9 1949, he was guest singer with the Ronnie Pleydell Band on the Light Programme.
(George had a long BBC history - starting as a 16 year old sound effects boy on Baird tv broadcasts in 1930; working on the first Radio Newsreels in the war, and going on to devise The Black and White Minstrel Show).
Jimmy was a radio regular from almost that first performance, on shows like Stars of Tomorrow on the Home Service and Variety Bandbox (in one 1950 edition, he starred alongside Les Compagnons de Chanson and 'Peter Sellers with Miriam Karlin). By 1951, Jimmy had his first hit, "Too Young", under manager Dick Rowe (the man who rejected the Beatles) and top billing on the radio with the Ray Martin Orchestra in support.
In 1953, he present Flat Spin ("a miscellany of records") on the Home Service. This may have been the BBC's first 'unscripted' music show. The rest you know.