In 1954, he had begun working with Tony Hancock in his BBC Radio series "Hancock's Half Hour". Having seen him in "The Lavender Hill Mob", it was the idea of Hancock's writers, Ray Galton and Alan Simpson, to cast James. He played a character with his own name (but having the invented middle name Balmoral) who was a petty criminal and would usually manage to con Hancock in some way, although the character eventually ceased to be Hancock's adversary. With the exception of James, the other regular cast members of the radio series were dropped when the series made the transition to television. His part in the show now greatly increased and many viewers came to think of Hancock and James as a double act.