Happy Valley star on stage in powerful courtroom thriller

He will be stepping into the Paul Newman shoes when the play reaches the Yvonne Arnaud Theatre, Guildford (July 4-8) on tour.

Jason is playing Frank Galvin, a washed-up veteran lawyer and an alcoholic. He is presented with one last chance to redeem himself when he is given an open-and-shut medical malpractice case that no one thinks he can win. Up against the unforgiving medical establishment, he convinces the family of a young mother – who was left brain damaged following complications during labour – to refuse a seemingly generous out of court settlement, believing it is negligence that has condemned this young mother. Convinced of a cover-up, he takes the case and the entire legal system to court.

“When I was offered it I didn't look at the whole film. I didn't want Paul Newman's brilliance in my head. I wanted to approach it fresh from the point of view of character but I just reminded myself of a bit. I looked at the closing arguments which in the film are very different to the book and to the stage version. In the stage version it is very focused on the closing arguments and on him trying to win the case but in the film I think they were able to do something a bit more. In the theatre you have got to be put across those arguments in a convincing legal way.

“Frank Galvin is a flawed human being. He is an addict and he's got a strong history of addiction through his family. He is a philanderer and he is separated from his wife. His children have grown up now but in this adaptation they took the decision to accentuate the love story a bit more. He is looking for redemption not just in the case but also in his personal life.”

Jason is known for his roles in Agatha Raisin, Emmerdale, Casualty, Waterloo Road and many more. But it was theatre where he started out: “Theatre has always been there though my love of acting originally came from watching old movies that always used to be on TV in the afternoon. After 11 o'clock they had nothing else to fill the schedules! I did a little bit of stuff at school but my real love of the theatre was from leaving art school and getting into the fringe scene, devising and touring plays. I did that for about five years before I ever got a screen role.”

Most recently he was on our screens in the final series of Happy Valley: “It was daunting. It was wonderful. My first day was my biggest scene with James (Norton, the villain of the piece). We were starting already on a cliff edge and it was really interesting the research into how modern policing works. I was playing one of the interviewers which is a specialist role. The police have specialist training but we weren't allowed to see that. It’s very specialist training for how they can tell when someone is lying or how to calm someone down how or how to get the confession… obviously without booting them over the head! We just had to guess about that, but one of the great things about the series was that it was so authentic about the way the police work.”