Interview: The sexiest bloke on the box

I think I must have first clocked the actor Steven Mackintosh when he played the mysterious John Rokesmith (alias John Harmon) in the BBC's adaptation of Dickens's Our Mutual Friend. "Hmm, he's quite something," I thought. "I like him." Next, it must have been as Joe, the romantic lead in the film The Land Girls, which co-starred the disgustingly pretty Anna Friel whom (as part of the plot) he got to sleep with. In fact, he also got to sleep with her in Our Mutual Friend, now I think about it, but I chose not to let it bother me on either occasion.

After all, and as my mother always told me, what I lack in looks I more than make up for with bags of something that might be personality, but then again might just be bags. (Tesco, Safeway, Sainsbury, Waitrose, Kwik Save... I compulsively collect them all, God knows why.)

And then, thirdly, it was as the dark, disturbing Tom in the BBC's dark, disturbing cop drama Undercover Heart, where he got to sleep with Daniela Nardini, which I didn't mind so much, because she's quite big and Scottish and possibly part-horse.

Anyway, by the time Undercover Heart came along, I was terribly in love, and practically considered ourselves married, with golden-haired children who happily agreed to wear cute sailor suits and didn't mind when Mummy had to go to Hollywood with Daddy, because Daddy was up for an Oscar, and Mummy had been offered the loan of a dress from Versace. "It was promised to Julia Roberts, actually, Mrs Mackintosh. But as it's you..." Anyway, I think when you get this far with someone, you possibly ought to meet them.

So, astonishingly, I fix it. I say "astonishingly" because, generally, I am as dynamic as a dead slug after it's received a massive cosh on the head. But I get his agent's number, and call, and before you know it we are due to meet at the restaurant Granita in Islington.

Granita is a very chic, New Labour sort of place. I arrive first, and am spectacularly nervous. I am looking quite nice, though, in some extraordinarily elegant combat trousers which I thought about ironing until I realised I don't actually have an iron. I think I would have shredded the napkin, had it been possible, but the Granita napkins are linen or something, so I just end up unpicking a few hems.

There's a fine-looking woman in high heels and a soft, expensive-looking, scarlet leather jacket sitting at the next table. When Steven arrives, he makes straight towards her table. "Coo-eee. Over here!" I have to cry. He has to quickly change direction. "You were hoping I was that woman, weren't you?" I say. "I wasn't," he protests. "Were," I say sulkily. "Wasn't!" he repeats. I tell him that if we go on like this, we will have to make an appointment with Relate. Think of the children, Steven! He is starting to look quite frightened.

He is exceptional-looking. He isn't, thankfully, handsome in that overrated, hunky, Tom Cruise sort of way. He is quite small, scrawny even, with girl's hands, yet he has the most beautiful face - serious, intense, wintry, subtly reactive. He has very blue eyes. There is a real kind of power to him. As an actor, he has that certain something which you can't explain because, if you could, he wouldn't have it. It might be a kind of cocktail of vulnerability, danger, intelligence and total fanciability. But, then again, it might not. I mean, what do I know, apart from the fact that Sainsbury bags seem appallingly flimsy in comparison to the Waitrose ones, which seem to be better made all round?

Anyway, I wonder whether he thinks he has a certain quality. At least an astonishing physical presence, if nothing else. He gasps: "God, no. I think of myself as a pointy-faced weirdo. Too angular, too spindly. I should really do more of the gym thing." He says that sex-scenes always terrify him. He's panic-stricken for weeks beforehand. "It's such a strange thing to do," he says. "And while you're doing it, you're aware that people are ultimately going to see this spindly little thing writhing around on a bed."

He is wearing old jeans, an old woolly jumper that might have come from Oxfam and an old coat that looks very The Red Cross shop on the Holloway Road, and which I think I almost bought once. He is quite creased, too. "I don't have an iron either,' he admits, which makes me even more certain that we have a great future together. He is wearing a chain around his neck with a chunk of stone threaded on to it - "It's a lucky stone I found on a beach in Suffolk' - and a silver identity bracelet "that my wife saw in a shop in Norfolk..."

Your wife, Steven? "Yes, my wife saw it in a shop in Norfolk and..." YOUR WIFE, STEVEN! "Yes, my wife saw it in a..." OK, how long has this been going on? "Well, we just celebrated our 10th anniversary and..." CHILDREN, STEVEN? "Two girls. Martha, six, and Blythe, two." So you were trapped early, then? "My family are the most important thing to me," he protests. Yes! Yes! I cry. I feel the same! My family are the most important thing to me! I'm not just some pathetic saddie who lives surrounded by supermarket carrier bags and falls for blokes off the telly, you know! I, too, have a very rich family life. Although, that said, if you did want someone to go the Oscars with you, I could possibly manage it. He says hang on, he's only just acquired an agent on the West Coast. "And I haven't even ever been to LA yet!"

He's 31 now, but made his stage debut at 12 at London's Bush Theatre, and has been working consistently since. In Prick Up Your Ears, the celebrated film of Joe Orton's life, he played young Joe in the childhood flashback scenes. In the Adrian Mole television series, he was Adrian's trainer- obsessed mate Nigel. More recently, it was as a scary, murderous nutter who fed his victims to his dogs in Prime Suspect 5, plus major film roles in Blue Juice and Lock Stock & Two Smoking Barrels. I think, now, he is possibly on the brink of being HUGE. I think, shortly, he'll be up there with Gary Oldman and Tim Roth and Ralph Fiennes and all the other English actors who have that certain inner stillness, which Hollywood so loves.

He, however, insists that he has no ambition in this direction. "I'd like to do a contemporary London thing, working with like-minded people, possibly through improvisation," he says, in his sweet, rather earnest way.

Fame? Does that attract you? He says he has just reached the point where people are clocking him in the street. It's OK, but quite disturbing, especially as most can't quite remember where they've seen him before. "So it's: `Were you at Leicester Poly with me in 1982? You were, weren't you? Don't deny it.'"

We have a very nice lunch. He is a very real bloke. He's a woman's bloke, I think. He lives locally, near Arsenal football ground, but isn't interested in football in the least. He lives almost entirely with females. Even his dog is a girl. The only other men in the household are some fish. "My guppies. And the males are after the females 24 hours a day, trying to impregnate them. All the girl fish look as if they're thinking: `Bugger off. You've had me already.'" He says he cried when his daughters were born. "Just this uncontrollable sobbing, because they were so beautiful". We talk a lot about his daughters. Blythe, he says, has fabulous chubby cheeks. Martha wants a doll's house for Christmas. Martha's brilliantly girly and invites her father to endless mock little tea parties.

Martha's a bit upset at the moment, though, because her friend Jessica has told her fairies don't really exist. Steven has had to convince her that maybe they do. We agree that children are wonderful, because they can be so easily duped. I tell him that if his daughter ever asks where God lives, for example, he might want to say he lives over Waitrose on the Holloway Road, with six angels who act as a remote for the telly, and a cat called Louise. I add that I told this to my own son once, and it satisfied his curiosity until he was at least 17. Steven says he knows this particular Waitrose well. It's where he does his weekly shop. I say, if you want to come back afterwards to see my Waitrose bag collection, you'd be most welcome. He says with great regret that he has to pick Martha up from somewhere shortly. He is truly disappointed, I think.

He was born and brought up in Sawston, which is just outside Cambridge. He feels no great attachment to the place. "I think it might have been a fairly pretty place once, with 13 pubs on the high street. But then it became one big Sixties housing development, and very new-towny. Our house was one of those standard, Sixties, Lego-shaped things.' His mother, Dorothy, is an office worker, while his father, Malcolm, is a builder. He has one sister, Linda, who is now a childminder. He says his first passion was not for the theatre or anything, but music. He used to have this wind-up gramophone, he says, which he called his "thirty bob" because it cost him thirty bob, and he carried it everywhere with him. It may have been a kind of early ghetto-blaster. He loved the "cheap end of disco music - Sister Sledge, Boney M - before graduating to Pink Floyd, "and writing their names all over my denim jacket, and all that rubbish".

Steven is still music-mad, and spends most of his money on CDs. "I have finally trained myself to be able to walk past a CD shop. Sometimes."

He thought at one time that he might be a rock star. He taught himself the guitar a bit. He sang a bit. But then he discovered that he was a good mimic.

However, he says that, as a boy, he was quite awkward and shy and uncomfortable in his own skin. He didn't easily make friends, he says, until he discovered a gift for mimicry, which made him quite popular at school. He is, he admits, the absolute cliche of the actor who became an actor because he found it easier being someone else than himself.At 12, he came to London to appear at the Bush, in a heavy play about Aleister Crowley. "There was a naked man in it. I had to run on, swearing and cursing."

He left school at 16 and got his big break as the lead in the National Theatre's production of Neil Simon's Brighton Beach Memoirs. Here he met his wife, the actor Lisa Jacobs. "It wasn't love at first sight. I just thought: `She's nice.' I was playing a character who was obsessed with his cousin Nora, and she was Nora. It was great when it happened for real. Fantastic."

He went on to do three of Shakespeare's plays - A Winter's Tale, Cymbeline, The Tempest - for Peter Hall, but it wasn't really his bag.

"I just wasn't meant to do Shakespeare. I'm not vocally equipped; I've got this flat, nasal, East Anglian voice. I got to understand the fantastic words Shakespeare wrote, but never got to fly with them."

He wasn't, initially, that keen on playing Rokesmith/Harmon in Our Mutual Friend. "I thought I'd do terrible Period Acting." What, as encouraged by the BBC Bonnet Department? "Yes. I thought I was going to be awful." You weren't, though. You were gorgeous. "Oh. Thank you... but it wasn't easy. I had these huge, convoluted sentences. Then I realised it was a matter of finding the truth in it. If you do that, you don't have to worry about, say, giving a performance that's too big or too small."

He's quite earnest, as I said.

Anyway, he has just finished filming a drama for Carlton TV, in which he plays a priest. Next, there's the possibility in February of a British film made with American backing. Now, though, he's off to pick up Martha. I get a little hug, and off he goes, while I race home. I don't like to leave my carrier bags for long. They get lonely and upset and so clingy, it's almost murder getting them off to school the next day.