Casualty actor Ian Bleasdale who plays paramedic Josh Griffiths is to leave the BBC show after 18 years.
Bleasdale has been at the centre of several explosive storylines
Bleasdale is one of the longest-serving cast members, alongside Derek Thompson who plays his friend Charlie.
The actor will bow out at the end of this year, but the BBC said the door would be left open for Bleasdale, 55, if he wished to return.
The popular medical drama began in 1986 and has since spawned spin-off series including Holby City and Holby Blue.
Bleasdale's character has suffered his fair share of heartache since he joined the drama . He lost his family in a house fire, was left for dead after being been stabbed, has been falsely accused of abuse and manslaughter and divorced wife Colette.
The new series of Casualty begins in September on BBC One. Storylines include an explosion which leaves the team struggling to cope.
The show won in the best continuing drama category at this year's Bafta TV awards, beating opposition from soaps Emmerdale, EastEnders and Coronation Street.
Following last year's Casualty 1906, a new three-part historical medical series titled Casualty 1907 will show life in a hospital in London's East End 100 years ago.
Alfie Allen, brother of pop star Lily and son of actor Keith, has landed a role in the spin-off as a gang member.
The BBC One programme, to be filmed in Liverpool, will be shown in the autumn.