Best known for comic roles in shows like The League of Gentlemen, this week Reece Shearsmith plays convicted wife killer Malcolm Webster in ITV’s new three-part thriller The Widower.

Here, he describes getting inside the mind of a murderer….

Malcolm Webster was jailed in 2011 for drugging then killing his first wife in a staged car crash then attempting to murder his second in a similar way for financial gain. How did he manage to con these women?

“Webster was totally charming and that mask never slipped; his first wife Claire, played in this drama by Sheridan Smith, felt completely safe with him. He was just this ordinary, nice man, who people couldn’t see was deceiving them. You’d think all of these women must be idiots, but they were actually all very strong women – he just got to them.”

What motivated Webster to carry out his crimes?

“Some people who’ve run up credit card bills and can’t see a way out kill themselves, whereas Malcolm drugged and killed a woman who dared to challenge him. In the scenes where Webster is drugging Claire, he’s still talking to her, almost reasoning with her. Webster had started to believe his own lies and that he was the victim.”

How hard was it to play somebody real, who’s still alive?

“The weight of responsibility is heavy. I’ve never played a role where it really matters; people’s lives were ruined by this man, so it was important I played him sensitively and not as this ‘mad baddie’. There’s nothing delicious about Webster, he’s just a mundane monster.”

Did you meet Webster himself before or during filming? And how important was it to have the support of those who knew him?

“Well, Webster still maintains he didn’t do anything, so it wasn’t like we needed to speak to him. But Peter Morris, Claire’s brother, Felicity Drumm, Webster’s second wife, and his third fiancee, Simone Banarjee, all wanted this drama made. I remember one day, Peter was watching me play Webster and told me I’d really captured his arrogance.”

We know that, in a later episode, you shave your head as Webster tries to convince Simone he has cancer. How did you feel about doing that?

“They filmed me actually doing it, which was quite scary, but I think it shows the commitment of Webster, so it was important we did it properly.”

What did your family think of your shaved head?

“I Skyped my family to show them and my kids were like: ‘Oh Daddy, you look stupid, put your hat back on.’ When my hair finally grew back, it felt like Webster was finally gone, too.”

The drama is set in Aberdeenshire and New Zealand…

“Yes, it’s set in those two places, but was all filmed in Ireland, so it was nice to go to Dublin but we missed out on a trip to New Zealand! But being away from home meant I could completely immerse myself in the role.”

You’re known for your comedy creations – how pleased were you to land the lead role in The Widower?

“I was so pleased to be thought of as an actor and not just a sketch show person. I think I got the part of Malcolm Webster because ITV thought I was the right person to play him and not because they wanted an ITV name, which sometimes does happen. I felt I’d earned it and I really believed I could do it.”