Mark Strong is used to playing the bad guy – it’s something British actors enjoy, he tells Steve Pratt ‘WHO did you just have?” asks Mark Strong, entering the room for his round table interview. Your director Eran Creevy, we tell him.

“Now he’s really ebullient and effusive, so I’ll have to be energised. James is a little more guarded, cautious.”

The actor prepares for an interview – one in a day-long series of print and TV chats to promote his new British thriller Welcome To The Punch – as thoroughly as he does a part. The role in question here is that of an ex-criminal who returns home to Britain from his Iceland hideaway when his son gets into trouble, only to find his old police adversary (the James he mentioned earlier – James McAvoy) is hot on his trail.

It’s one in a long list of movies that Strong has made over the past decade. Body Of Lies, Robin Hood, Kick Ass, Zero Dark Thirty, The Young Victoria, The Eagle Of The Ninth, Sherlock Holmes, Green Lantern, John Carter and Tinker Tailor Soldier Spy, to name a handful.

In many he’s been cast as the bad guy so it shouldn’t be surprising if he discusses the art of screen villainy. He doesn’t approach playing good or bad any differently. “You play the person first and whatever attributes that person has, you find whether they’re good or bad,” he explains.

“I’ve seen actors play villains that are so twodimensional.

I don’t mean to disrespect them, but often American character actors have found it difficult to play the villain because they grew up with a hero culture. It’s all about the guy that wins and the guy that’s the hero.

“So when they come to play the villain it’s always a pastiche, it’s not real. Whereas we grew up with Richard III and Macbeth. We understand that villainy is inherent in human nature and British actors enjoy playing it.

“What I’ve learnt is that the person comes first, not the villainy or the goodness. Actually, if you infuse a villain with good traits and vice versa, a good guy with something a little bit suspicious, that always makes them more interesting.” This is said without sounding pretentious. He needs to find something in a character to explain his bad behaviour, to give him a hook for the villainy.

He points to Lord Blackwood, his role in the Robert Downey Sherlock Holmes movie. “He was a big classic panto villain type whose reason for being in the script was as a dark malevolent force that the hero has to capture.

“Even in him I found the thing that made him the way he was. You have to find something or you’re adrift, just playing general good or bad.”

All this makes it easier to leave his villains at work and not take them home with him. “It’s an acting job so I can run around firing a gun being a bad guy and then, of course, go home and my life isn’t like that,” he says.

The role he’s filming at present – as a psychiatrist in a movie with Nicole Kidman and Colin Firth – is probably the closest he’s played to himself.

There’s nothing about him that’s “character- ful,” he says. “He’s just a doctor, a guy, and basically I have to play him as if he’s me.”

This is difficult because he comes from the theatrical tradition, which is about transformation, putting on wigs and cloaks and pretending to be someone else.

“I love doing that. I loved it in Zero Dark Thirty – the new film about the capture of Osama bin Laden – people didn’t know that was me. It was just a wig and an American accent. People weren’t expecting to see me in that movie and were like, ‘oh my God’. I love confounding people’s expectations.”

His career has gone in phases. There was a decade of theatre, followed by five years or so of TV (including Our Friends In The North) and then movies took over eight years ago.

“I haven’t done a play since Twelfth Night and Uncle Vanya for Sam Mendes, which we did in London and New York. I loved it, but haven’t done anything since. It’s always there to go back to, but I feel as if I want to keep moving forward.

“Luckily, things keep coming through that I want to do. Like this American TV series. I never wanted to go to the US and be away from my family, but it was something I couldn’t say no to.

“And when I look at the parts I’ve been playing recently – how can you say no to Kathryn Bigelow or a character like Frank D’Amico in Kick Ass? Or say no to working with Ridley Scott in Robin Hood and Body Of Lies?

“The things I’ve done, it’s been impossible to say no to. It just so happens these things keep coming. Long may it continue.”