On my way to interview Tom Hardy in London ahead of the release of Warrior and his latest intense, physically-transforming performance, I notice a bodyguard planted at the door. This is presumably for insurance purposes – the man is, after all, at the helm of two blockbuster franchises over the next year – and not to cast any doubt on the actor’s capacity to look after himself.

Because when Hardy appears, he is, put frankly, enormous, but with nothing to spare and sort of balletic in his movements like a boxer. A thin hoodie and tracksuit bottoms complete the look of an athlete at rest.

His incongruous, high-pitched giggle belies all this ridiculous amount of effort in an instant: “You just do what you have to do for a role. It’s all part of the deal, like turning up on time on the factory floor.”

Hardy may have become the go-to film artiste for such physically demanding roles – think Christian Bale with bulk – but he holds one director in the greatest respect.

“When Christopher Nolan throws a ball, I go fetch. I just feel incredibly lucky to be working with a man of such imagination and technical ability. Long may it continue. He’s on a roll.”

Which could equally describe Hardy. He’s been ploughing on for a decade or so (roles in Band of Brothers, Black Hawk Down, RocknRolla), but it was three years ago when he overwhelmed audiences with his portrayal of Britain’s longest-serving inmate Charles Bronson – theatrical, camp, menacing by turn. Since then, he’s built on this dazzling breakthrough with a catalogue of compelling turns – as Heathcliff for Wuthering Heights on TV, and to worldwide recognition as Eames in Nolan’s mould-breaker Inception.

He’s currently on the big screen as establishment outsider Ricky in the re-working of Tinker Tailor Soldier Spy, after stepping in as a last-minute replacement for Michael Fassbender, and will soon be off to Australia to take the lead in George Miller’s reboot of the Mad Max franchise.

If Hardy is quite obviously climbing the rungs of the A-list ladder, he remains adequately humble about his escalating fortunes:

“You don’t see a great scheme unravelling before you. Like any actor, it’s just one job at a time.”

If he does reflect on the past couple of years, it must be with a wry satisfaction, though. A former model, he previously battled alcoholism and drug addiction before entering rehab and becoming sober in 2003.

Today, he only refers fleetingly to previous troubles, saying, “It would be easy to look for hooks in my own past, but the script is so complete, with a complete back story for each of the characters that I really didn’t have to.”

Warrior is painted in broad brushstrokes – two brothers, both talented proponents in the sport of Mixed Martial Arts (to the layman’s eye, this just appears that, in the ring, anything goes, but I’m sure it’s actually a highly skilled business). These brothers are, inevitably, separated by circumstance and personal values until they meet, guess where, at a MMA contest where both have out-of-ring demons to conquer.

For Hardy and his co-star, Australian actor Joel Edgerton, this meant months of physical work to prepare the scarily buffed torsos we see being beaten to high heaven, and Hardy is easy, almost gleeful on the kind of effort required to achieve the convincing power and ring-torture:

“It’s not really work, is it?” he signs off with a grin. “I mean, don’t get me wrong, we take it seriously and everything, and give it our best shot, but there are far, far worse things I could be doing.”

Warrior is on UK release from Wednesday 21st September.

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