The Robin Hood heart-throb Richard Armitage is joining the cast of Spooks. Our correspondent met him

Richard Armitage wants to make your skin crawl. No, really. The 37-year-old small-screen sex god has had it with beauty. He’s tired of being that guy, the Guy of Gisborne guy, the one from Robin Hood in the snug leather trousers and buff torso who pops up in YouTube montages with titles such as "Sexy Boy”, and sends legions of his obsessed female fans – the so-called "Armitage Army” – into paroxysms of orgasmic delight. No, he says, "I want to play characters that are disgusting, and who look ugly and crap. I’m quite happy to do that, and, in fact, I’d prefer to do that.”

And as if to prove a point, Armitage has battled his way on to the seventh series of the award-winning spy drama Spooks by toning down those dark, poster-boy looks. "My character, Lucas North, has been banged away in a Russian prison for eight years, and is now back but carrying a lot of baggage,” he explains, sipping tea in the meeting room of a central London publicity firm, and looking every bit the modern Adonis in denims and black bicep-hugging T-shirt. "So I fought hard to make him look as shocking as possible. I lost a stone in weight, and wanted to shave my head, but the producers, who are catering for that section of the audience you’re referring to (the Armitage Army), wanted him to look attractive. So in the end there was a compromise.”

And true, the Lucas North revealed so far in teasers and trailers is hardly a malformed troll, but there seems to be a certain wiriness there that might come as a surprise to those familiar with Armitage’s beefy smouldering in Robin Hood or his galumphing period swagger in the breakout mini-series North & South. He is naturally sworn to secrecy about the blow-by-blow narrative details of Spooks 7, but he does guarantee two things. One, that it will be more Bourne than Bond. "Don’t get me wrong, I love James Bond,” he says. "But he’s a fantasy hero, and Jason Bourne’s just more relevant today, and more of an everyday guy.” Secondly, he reveals, the series will be propelled forward by the vexed question of North’s loyalty to MI5. "There’s a lot of suspicion around him,” he says. "He stinks of double agent, and though there’s a need to trust him, there’s also a serious danger of security breach.”

He says that North is personable on the outside but buckled and damaged within, just as his startling Guy of Gisborne was outwardly aggressive while searching for inner harmony. He adds that for some inexplicable reason he seeks out these tensions in his work. "If I’m offered the role of the hero, I immediately look for the antihero within!” he says. "I see everything in terms of an outer skin and an inner skin.”

Armitage suspects that this addiction to duality comes from his own life, and more specifically from his experience of being a crushingly shy Leicester teenager who was drawn to the stage yet loathed being observed. The son of an engineer father and secretary mum, he went to a vocational secondary school in Coventry and was immersed in music and drama, but seemed unable and unwilling to face the spotlight. "I was told that I had an aloofness about me, and that really bothered me,” he explains. "Because it wasn’t aloofness, it was shyness. It made me realise that what was going on inside of me wasn’t being reflected on the outside.”

Although Armitage never managed to reconcile the two sides of himself (he is still crushingly shy today – "If I never had to walk down a red carpet again for as long as I lived I’d be a happy man”), he nonetheless parlayed his neuroses with style, enrolling in LAMDA, joining the RSC, and eventually, after a series of roles in shows such as Casualty and Cold Feet, turned heads as the glowering mill owner John Thornton in North & South.

It was his performance as Guy of Gisborne in the new retooled Robin Hood, however, that was the revelation. Here, somehow, he turned convention on its head by winning unexpected audience sympathy from the vulpine villain. "It all came from a moment in the first episode when Guy is looking at Robin,” he explains. "You realise that they’re both the same, and that Guy’s thinking, ‘I could’ve been good. I could’ve been loved!’ Which is tragic.”

He flinches, nonetheless, when he hears of an industry rumour suggesting that Robin (Jonas Armstrong) is to be killed off, and the series remoulded around Guy. "That’s news to me!” he says, shifting nervously in his seat before adding, carefully, "Well I think I’m on the wrong side of 30 to be hopping around in trees. And Jonas is doing a really good job.”

For now, though, he says that his life is a balancing act between the personal and professional worlds. He lives in London with his girlfriend (sorry ladies!) who, he says, works in theatre and understands the crazy lifestyle he’s chosen. "I try to keep her separate, and not involve her too much,” he says. "You give as much as you can to the job, but you have to keep something back for yourself.”

He is currently working on a long-gestating biopic of Richard III that will, apparently, redress the imbalanced portrait created by Shakespeare and also involve an "ugly” makeover. And still, he says with a sigh, he’s also aware that for the moment his beauty remains the issue, and something of a double-edged sword. "When I get to 50 and everything’s hanging on the floor and looking like s***, I still want to act,” he says, contemplating the unthinkable. "But, right now, if it means I keep working because I have some kind of fan base, then fine . . . But it does disturb me slightly.”