John Simm: 'I don't mean to seem cocky'

'I was trying," says John Simm, "to find a way to do Hamlet." Er, sorry? The man who played The Master in Dr Who, and a leather-jacketed detective in Life on Mars, and a clubber in Human Traffic, and a loan shark in Never Never, and a scheming Puritan soldier in The Devil's Whore, the man who has only been in two stage plays since leaving drama school, wants to play the most challenging role for a young actor in the history of theatre? Having never been in a Shakespeare (outside drama school) before? Having only ever seen one production?

"Yes, why not?" says Simm. No, I bluster, no reason at all, I'm sure you'd be brilliant. I am, in truth, a little bit nervous. The man sitting in front of me, in a scruffy, draughty room in the back-stage labyrinth of the Union Chapel, has a reputation as a reluctant interviewee. The words most frequently used of his performances on TV and screen are "edgy" and "intense" and the word most frequently used of his performances in interviews is "cocky". He has just wolfed down an egg and cress sandwich, and, in his (slightly strange) combination of stripy polo shirt (very Life on Mars), tweed jacket, beige trousers and baseball boots, is all poised politeness, and elfin, tousled charm. But there is – yes – a slight edge. It wouldn't take much, I can't help thinking, for that polite smile to slip into something closer to irritation.

I've asked him about the play he's rehearsing, of course, and he's told me, of course, that it's "a hell of a challenge", and that he was "intrigued" by the script, and the fact that it's "like a split-screen on stage", and that he's playing two characters, a detective (again) and a violent, alcoholic neighbour. And then he announces, casually, that he "wasn't particularly looking to get back on stage again", but was wanting to do Hamlet. Whoa! And he hasn't done any Shakespeare before? "No." And wouldn't it feel a bit like following in the footsteps of David Tennant? "I didn't really think about that." And he's only ever seen one Hamlet? "Yes, at drama school." And doesn't it, um, imply quite a lot of confidence?

Simm looks baffled. "I guess so," he says. "Yeah, I guess so." It's just, I say, that I saw him on Jonathan Ross, saying how good his music was – he used to be in a rock band called Magic Alex – and Ross said "how vain", and it's rather unEnglish to sing your own praises, isn't it? "I guess so," says Simm again. "Look," he says, with just the faintest trace of that feared-for irritation, "I don't mean to come across as cocky." Well, I say, you did once say "cockiness is the thing, as long as it's not misplaced and you come up with the goods." Simm laughs. "Did I say that? Was I really young? Look, we've got on to a really weird tack here, with the Hamlet thing... Yeah, course I think I could do it. Why not?"

And why not indeed? John Simm is one of the hottest properties in British acting at the moment, a name mentioned in the same breath – and with the same awed sense of streetcred and boyish sex appeal – as David Tennant and Dominic West. Since leaving drama school in 1992, he has never been unemployed. He started with a small part in Rumpole of the Bailey, followed by a psycho in The Bill, a burglar in The Locksmith and a troubled teenager in Cracker, but it was in 1997, with Jimmy McGovern's series The Lakes, that he hit the TV big time. Since then, he's worked with the best writers in the business – with Paul Abbott, in Clocking Off and State of Play, with Tony Marchant in Never Never and the BBC production of Crime and Punishment and, of course, with Russell T Davies in Doctor Who. His participation in something is pretty much a hallmark of quality. So yes, there's little doubt that Simm's does "come up with the goods".

All of this, however, has been on screen, mostly (slightly to his regret) the small screen. Stage is different – and, one assumes, night after night after night after night, rather hard work. Isn't it? "Yeah," says Simm, relieved that I've laid the ghost of Hamlet to rest. "I realised how hard it was 'cause of Elling. The run of Elling was long and I hit a brick wall half way though, and I thought 'I can't do this any more'." Elling, a comedy about two men just out of mental hospital, ran first at the Bush and then at the Trafalgar Studios two years ago. Simm was nominated for an Olivier Award for his performance.

"I thought, 'I can't say these lines any more,'" says Simm, "and that was difficult. But when I read this play, there was something about it that kind of stayed in my head." The play is Speaking in Tongues, by Andrew Bovell, a haunting thriller that was made into the multi-award-winning film, Lantana. "I needed," he says, "with a winning, boyish grin, "a kick up the arse. I'm not saying that screen acting became easy, but I thought 'do something that's going to be really hard – and terrifying! – so you feel alive again'. And I thought, 'this is the reason I became an actor'."

And is he – how can I put this? – in any way afraid of the audience, afraid, in fact, of his fans? "Well," he says, clearly trying to be circumspect, "my one stipulation this time was 'I don't want to see the audience'. A lot of over-zealous sci-fi fans, shall we say, came to see Elling, and they were shouting at me during the performance. At the end of one curtain call, I went up to this guy and swore at him quite loudly. I'm not great at dealing with the public in that way. I'm not the most sociable person in the world."

Poor John Simm! I feel myself warming towards this slight figure, trying so hard to be polite to me, to the nutters who accost him when he's out, accost him, it seems, even when he's just doing his job. During his hedonistic Nineties – when he had a brief relationship with Spice Girl, Emma Bunton – he had to stop clubbing, after the success of Michael Winterbottom's cult clubbing film, Human Traffic. During live gigs with his band, Magic Alex (now defunct, but resurrected for a wedding last week), he would "stare at the floor", partly, he says, out of natural shyness, but partly because people would be pointing at him and saying "that's the bloke from The Lakes". Fame, as even those begging for it discover, has its price.

But John Simm doesn't like talking about fame – he hates to sound ungrateful – and he doesn't like talking about confidence, and he doesn't, I imagine, after about a million interviews being forced to talk about Curly Wurlys and Starsky and Hutch (and other accoutrements of the Seventies that he's really too young to remember) like talking about Life on Mars, so I ask him instead about books. I know he loves books. When he moved down to London as a teenager, after a working-class childhood in Lancashire, he felt, he says, like a "fish out of water" and retreated into reading. "I've always got a book on the go," he says, "usually two. I think that's the best part of my job. For The Devil's Whore, I devoured these books on the English Civil War. For Van Gogh, I read his letters to Theo, which was a joy."

For Van Gogh, who he played in a Channel 4 drama, The Yellow House, he lived on black coffee in order to look appropriately hollow-cheeked. Simm trained in the Stanislavski school of method acting at the Drama Centre (a technique of total immersion that had Olivier famously saying to Dustin Hoffman "dear boy, have you tried acting?"). Was this the most "methody" role he'd done for a while? "If I get a chance," he says, "I'll give it rock-all with the old method. You don't really get the chance to use it on screen. Mind you, if I brought Raskolnikov [the murderer he played in Crime and Punishment] home with me, or Van Gogh, or The Master, the evil man of the universe, I'd have no marriage left..."

Ah, marriage. Normally, I might ask at this point about his home life, and his wife, the actress Kate Magowan, with whom he has an eight-year-old boy, Ryan, and a two-year-old daughter, Molly. But I've read that Simm hates being quizzed about his private life, so I plough on with the do-the-roles-you-play-affect-you thing. For example, Sex Traffic, a Bafta-award winning, and horrifically upsetting, Channel 4 drama about sex slaves in London?

"It does a little bit," says Simm. "You wouldn't be human if it didn't. Especially Sex Traffic. For once in my life, I thought 'I'm going to do something which might make a difference in a teeny, weeny way'." So does the rest of his work not? Simm looks bewildered. "Why would it? Like I say, it's a character. Usually, I'm a slave to the writing, and I try to serve that character as best I can. I've got to find some humanity with all the characters, even Raskolnikov. I have to sort of be on his side, which is why I could never play a paedophile."

Simm could never play a paedophile, I think, because his life was changed by the birth of his son. In interviews at the time, he spoke about life finally having meaning. He finds being separated from his children, on filming projects, "physically painful". And it's for his son that he agreed to play The Master in Doctor Who (he's doing it again in a Christmas Day special), but he now worries that the extra attention might cause him to get bullied. "I just wanted to make him proud," he says simply.

From the outside, it looks as though John Simm's life has been remarkably easy: happy childhood, wild, but also successful, twenties, domestically stable, and also successful, thirties, a continuing passion for music (not just rock, but also classical and ballet), a continuing passion for football and, of course, being brilliant at something he loves. Hasn't it? Bastard! Simm laughs. "There's been things which have been not easy, but yeah, you're right. I can't moan."

So what else does he want? Hollywood? "Well," he says, a tiny bit tetchily, "they know where I am, because they remake everything [State of Play, Life on Mars] I do. I don't know. I just want loads of money. Give me loads of money!" And if they did? Would he give himself some breaks? John Simm flashes the cheeky, sexy smile that has people stopping him in the street, shouting at him at the theatre, and sending him mountains of fan mail he doesn't open. "Oh, Christ," he says. "I'd probably retire. I love doing nothing. I love not working."

'Speaking in Tongues', to 12 December, Duke of York's theatre, London WC2 (0870 060 6623; www.ambassadortickets.com)