James Nesbitt (Jekyll, Bloody Sunday, Cold Feet) reprises his role as renegade undercover cop Tommy Murphy as Murphy’s Law returns for a fifth series.

In a gripping, three-part special, Murphy finds himself caught up in the dark, criminal world of people-trafficking and is forced back into the field to solve the disappearance of two undercover officers at a caravan site in Norfolk. As he searches for the truth, he has to immerse himself in the world of sex traders and prostitution.

When it transpires one of the undercover cops is dead, it’s a race against time to find the other missing police officer, Kim Goodall. But, as the investigation takes several turns for the worse, Murphy soon finds himself battling both sides of the law as police HQ tries to hide mistakes. Can Murphy hold his cover, keeping the investigation alive long enough to find Kim and bring down the criminal organisation behind it all?

In preparation for the role, James collaborated with ex-undercover officer Peter Bleksley, who has worked on Murphy’s Law as a story consultant since series three. With years of experience working in the field and facing many dangerous situations, Pete was able to help James further develop the character of Tommy Murphy in this series.

James says of Murphy’s character: “There was a life there a long time ago. There was a wife, a child and he lost all that. So what do you do? You either kill yourself or drink yourself to death or you immerse yourself in some place where you feel you belong. I don’t think it’s a comfort zone, it’s an instinct: ‘that’s where I belong, that’s what I do and also I get the opportunity to not be myself’, ’cause the more he does that, the less time he has to think about the horror of his life.”

On playing the role of Murphy, James says: “It would be easy to say there are similarities between being an actor and an undercover cop because there are in a sense. Good undercover cops are able to immerse themselves into that world, they are able to adapt. The whole thing is about being in the moment and that is quite similar to acting. They also have to be able to immediately embrace something and take it in.”

James has graced television screens as many well-loved characters. His best-known television performances to date include the lead role in Jekyll, Steven Moffat’s successful, modern-day version of Jekyll and Hyde for BBC One, and Adam Williams in the popular TV series Cold Feet.

His film credits include the award-winning Bloody Sunday, for which James’s performance as civil rights campaigner Ivan Cooper was nominated for a Bafta. He also played Pig Finn in Waking Ned and Ronnie in the film Millions.

This series of Murphy’s Law also stars Andrea Lowe as missing undercover cop Kim Goodall, Christopher Fulford as the seemingly untouchable criminal mastermind Mark Baker, Ian Redford as the career-driven Chief Superintendent Ken Bowry, Robbie Gee as Murphy’s long-suffering boss DCS Atwood and Jessica Oyelowo as fellow officer Jackie Cole.