Born in 1940, the youngest son of a Billingsgate market porter, Jason started his television career in 1964 playing the part of Bert Bradshaw in Crossroads.

In 1967 he performed alongside Eric Idle, Terry Jones, and Michael Palin in the television sketch comedy series Do Not Adjust Your Set. 

He also appeared in a variety of shows supporting stars such as Dick Emery, before his performances caught the attention of Ronnie Barker, who soon became his mentor.  In 1973, the pair starred together in Open All Hours.

In 1981 he found his most enduring and popular role, Derek 'Del-Boy' Trotter in Only Fools and Horses, created by John Sullivan, a series that ran until 2003.  In 1992, Jason moved to ITV to star as Detective Inspector Jack Frost, in a role that would continue for 16 years.

He was awarded an OBE in 1993 and a knighthood in 2005, both for services to drama.