Jason starred in London Weekend Television's "Lucky Feller" (1975–76), written by Terence Frisby and produced by Humphrey Barclay. About two brothers in south-east London, the series was in many ways a forerunner to "Only Fools And Horses", only Jason was in the more dopey 'Rodney' role with Peter Armitage playing the cleverer of the two. The brothers drove around in a comical bubble car, a precursor to the famous Trotters' van; and there was even the joke where, just as he was trying to impress the girl (Cheryl Hall), Jason casually leaned back against the bar, without his knowing that barman had just lifted it behind his back, and fell through. This situation was re-enacted in "Only Fools And Horses". He played the lead role of Peter Barnes in the ATV sitcom "A Sharp Intake of Breath" (1977–81), alongside Alun Armstrong and Richard Wilson. In 1979, he appeared as Buttons in the pantomime "Cinderella" at Newcastle's Theatre Royal, starring Leah Bell and Bobby Thompson, produced by Michael Grayson and directed by John Blackmore.