Hasn't Harry Potter grown?

Daniel Radcliffe talks to Lesley White about the new stage role that spells a radical change of image.

Daniel Radcliffe can't wait to get home tonight. Not because there is a contract to sign or a script to peruse, but because the Klaxons album should have arrived from Amazon. This is cause for excitement in a 17-year-old indie-punk-funk fan, no less for the Harry Potter star, with his wealth and adoring fans, and his collection of plastic comedy ears recently sent by a humorous Japanese contingent. He will listen to his new music in a bedroom stuffed with piles of old NMEs that his mother, Marcia, is constantly asking him to chuck out. This afternoon, he has been in rehearsals for his lead role in Equus, the most wholesome of our teenage icons having chosen the most controversial of plays as his vehicle of transformation. It has nudity, torrid sex, mental aberration, erotic obsession with a horse and nothing in common with the magical realm, save perhaps a passing fancy for centaurs. "A play to change how people think," he says reverently.

The story of a disturbed stable boy who has blinded six horses with a hoof pick is an unresolved exploration of the parameters of normal human behaviour, but Radcliffe's take on his complex character is refreshingly straightforward. "When I was 10 and I'd seen a Bond film, I'd go home and act out the characters," he says in his well-modulated tones (no teenage mockney, thank goodness). "Alan is doing that; he fantasises about becoming a centaur."

Young Dan has grown up. On a year out from the Potter schedule - the fifth film, Harry Potter and the Order of the Phoenix, is released in July, and he has signed up for the final two after that - he has chosen to diversify before he is eternally imprisoned in Hogwarts in the minds of an audience that is maturing with him. "Better sooner than later. To some people, I will only ever be Harry. I know that, I don't fight it. I don't want to distance myself from him. I'm proud of that work. But I do want to show them that I am not Harry Potter. I am an actor."

Equus is Radcliffe's first stage work, apart from a guest appearance in The Play What I Wrote (and before that as a monkey in leggings at infant school). He seems unfazed by the popular press's scrutiny of his toned physique and sprouting body hair, and simply asked his Potter co-star and friend (and, truth be told, idol) Gary Oldman for advice on being naked on stage. "He said the first night is terrifying, the second is pretty scary, and after that you don't care. When you do it in a cold room and you are nervous, everything goes a bit shy down there, but I have been assured it will be nice and warm on the night. We have done the nudity scene twice with our clothes off, and my acting improved so much. It's hard to show that vulnerability you need for nakedness with your clothes on. Now I get them off at the drop of a hat."

This may be Radcliffe's moment to grow up, but as he springs into a room at a hotel near his Fulham home, his piercing blue eyes burning a path before him, he seems vibrantly, impossibly young, a boy teetering on the edge of grown-up life, all bum fluff and occasional zits and no-girlfriend crises. Casual in his rehearsal jeans and jumper, he asks for a Coke and jumps up to silence the offensive background music; the only clue to his status is a gentle giant of a minder called Jason, his driver for the duration of the Equus production, just in case he gets "a few lunatic fans on the street".

Seven years ago, he was offered the chance to sign up for seven Potter pictures, all to be shot in Los Angeles, and his horrified parents turned the offer down flat, while 10-year-old Dan knew nothing about it. It was only after a chance meeting with the films' producer at the theatre, and a revised offer of signing for two movies, both to be made in the UK, that they cautiously relented. His father, Alan, a literary agent, gave up his job to act as chaperone; scripts are read and decided on en famille (his mother is a casting director). There is no sign of imminent separation, nor the longing for autonomy that usually propels young men of his age towards a place of their own. It is as if his life as Potter has bound him closer to his parents, his anchors and protectors, just as other teenagers are pulling away.

He acted very little as a young child: miserable at Sussex House prep school, in Chelsea, he was put up for a role in the 1999 BBC adaptation of David Copperfield by his mother, in a bid to boost his confidence - "and do something other kids wouldn't have done" - and won the role of young David opposite Bob Hoskins as Micawber. It was on location for his second film, John Boorman's The Tailor of Panama, that he heard he was to play JK Rowling's orphaned boy wizard, a promise of worldwide fame that would make his fellow Potter actor Robbie Coltrane declare that he wouldn't let his son do it. Similarly, Boorman was apparently heard to remark, at the time, "Oh well, there goes his childhood" - which makes Radcliffe indignant, for he disproves the common notion of a dysfunctional, indulged child star. The studios at Leavesden, just outside the bright lights of Watford, are hardly Hollywood Babylon, and he promises with an incredulous laugh that he was never offered drugs or booze on the Harry Potter set.

"We were kids in a theme park. I was swinging on the scaffolding, the bane of the costume department's life, constantly dirty and ripping the clothes. Anyway, I'm surrounded by honest people who, at the slightest hint of arrogance in me, would be quick to say, hey, get back in your place." Have they ever needed to say that? "I can't remember it ever happening. Potter is far bigger than any one person. You have to know that. If I turned around and said I'm not doing the last two, there would be added interest and more people would go and see them."

Although he has lived the past seven years in stellar adult company (notwithstanding his mate Rupert Grint and Emma Watson, with whom he bickers a bit), earning a fortune the size of which he has never asked (estimated at more than £5m), there is nothing about Radcliffe that seems more sophisticated or jaded than his years. Rather the opposite, in fact. He is clearly a ready protégé: respectful and grateful, an earnest learner from his extended family of Potter's knighted thespians. Looking for a play, he had discussed doing The Browning Version, directed by Kenneth Branagh, who also brought him into talks for Equus (which Branagh originally intended to direct, though that role fell to Thea Sharrock). His admiration for Oldman is incandescent, and one can see that the talented welder's son from south London would hold a special fascination for such a nicely brought-up public-school boy; as would the charisma of a short man, which Radcliffe, too, seems likely to remain. "Gary is 5ft 8in and skinny, but he is magnetic. I'm 5ft 5in, but I'm going to start calling myself 5ft 6in."

Acting has rescued him. He was never academic or sporty; he disliked school; university never held much appeal; he probably won't do his A-levels or return to formal education, though on the set of the next Potter movie, an English teacher will come in and read "difficult" books such as Ulysses with him, just for interest. He finds little in common with other boys his age, lacking the idling hours of a normal adolescence and the spontaneity for last-minute plans and hanging out. "It's not that I think they are immature, but I don't know what to say to them. I'm worried I might sound like I'm boasting, or might mention too many famous names. I find myself becoming overly timid and self-effacing, and watching what I say. I'm more comfortable with people who are a bit older, especially older girls, which is a real curse, because they are not interested in a younger guy." Currently single, does he worry he might attract attention for the wrong reasons? He laughs. "Are you kidding? I'm 17, and as long as girls are interested in me, that's fantastic."

When he returned to City of London School between films, the younger boys were awestruck and the older ones picked on him, though he is generous enough to believe they weren't driven by jealousy, merely by boredom and testosterone. "The insults were all pretty inane. It was just, 'Ooh, there's Harry Potter, let's have a go.' Because I spent time around adults, I was in a different place. I never got angsty about it. I could always say to myself that in six weeks I'd be back on set." The "hormonal agonies" of his teenage years have helped him present an angrier, more questioning Harry in the fifth film, which, he reports with satisfaction, is darker and more intense: "Harry is going through the same stuff."

Before that come Rod Hardy's December Boys, his first nonPotter movie, an independent Australian project about four orphans competing for a family, and My Boy Jack, an ITV drama to be shown on Remembrance Day, in which he plays Rudyard Kipling's myopic 17-year-old son, killed at the battle of Loos in 1915. "The film is about pro-war Kipling's sense of loss and guilt," he says, adding thoughtfully that his own family have never wanted him to be anything other than happy. Next year, he will be back on set in Leavesden, and though he is proud that so far the producers reckon "only 15%" of Equus tickets have been purchased by Potter maniacs, he can't help but look forward to reconnecting with the character who has given him a career he never even knew he wanted.

"When I've shot the last scene of the last movie, I will be devastated. Harry Potter has provided my friends, seen me through my exams. I've had my first girlfriend, my first kiss. It's been my life." Does Harry need to die for Radcliffe to be finally free of him? "I want him to die because I have a melodramatic yearning for a death scene. And the prophecy in the fifth book says only one of Harry and Voldemort can live. Or is it that neither can live while the other survives? Oh God, what is it? The fans will kill me if I've got that wrong."