Sean Bean is having a day off. Or at least he thought he was until he ended up doing this interview. But that's the way it's been for the last 18 months for the former welder who has turned into one of Britain's biggest exports to Hollywood. In the past five years he's become one of America's most in-demand actors, starring in one big film after another:

Don't Say a Word, The Lord of the Rings: The Fellowship of the Ring, Troy and National Treasure. And this summer alone he's got two more coming up: The Island, with Ewan McGregor, and Flightplan, with Jodie Foster.

No wonder he looks knackered.

The 46-year-old is gaunt, and a lot thinner than you might expect. Perhaps the strain of having worked constantly for almost 18 months is starting to show - or perhaps he is just one of those stars who looks much better on-screen than off. Today he is wearing an old, faded T-shirt, a pair of jeans that are not so much distressed as crying out to be put out of their misery, and a pair of trainers. This was supposed to have been a break of a few days at home in London before heading back to work (Toronto, this time, to finish a leading role in Silent Hill, a big-screen adaptation of the hit computer game).

As he ushers me in to a hotel suite that has been rented for the afternoon, he is amiable but a little ill at ease. It can't be the surroundings making him uncomfortable - after all, he should be used to London hotels, having lived in one for three months last year when a burst pipe flooded his Belsize Park home. It's probably more to do with the fact that he's here at all: Sean Bean gives the impression that if offered the choice of being interviewed or smeared with honey and staked over an ant hill, he'd have to have a good long think about the options.

Still, he's nothing if not professional. He settles back on the sofa, orders some coffee and starts to chat amiably about how busy he's been. "It's why you become an actor - to do all the parts, " he explains. "When you're working you want a break - and then when you have a break you want to work. It's a bit like school, really, " he says, and laughs.

The other problem for any actor, of course, is that if you take too long a break then audiences have a nasty habit of forgetting who you are. The maxim that the show must go on has a lot less to do with professional duty than the possibility that your replacement might be a better actor. Bean's agent frequently frets about this, the actor admits, and often halfjokes that he might disappear if he stays away too long. Living in London, Bean is already half-invisible as far as the Hollywood social whirl is concerned - but he thinks he might have to call his agent's bluff.

"You need to have a break now and then, " he says running his hands through his shock of sandy hair. "When I finish this next one [Silent Hill] I'm going to have a couple of months off and just be at home. I've been away from home for such a long time. Six months for Troy - that was a long one - and straight from that to National Treasure, and that took me until Christmas so I was almost a year away. I was home for two weeks at Christmas and then back again. It's great that you're doing things you're interested in - it's exciting, you're travelling - but it's nice to recharge the batteries and not think about anything."

It's a stiflingly warm day, and there is a hint of fatigue in his voice as he struggles to make himself heard above the roar of the traffic from the main road outside. As he thinks more about his workload, Bean confesses that lately he has been finding it hard to relax. Whenever he finds himself doing nothing he convinces himself he ought to be doing something, and it takes him a while to wind down. Also, an actor's work is not finished when the cameras stop rolling for the day. Given the frantic nature of most productions, not to mention the constant script changes, there are always new lines to be memorised for the next day as well as costume fittings, make-up tests and dozens of other things that can eat into your time.

"It's difficult, " he says, his accent becoming more and more broadly Sheffield with every word. "You have a big week and you're filming every day and in every scene it takes quite a while to wind down. It's easier when you have a week where they only want you for two days of opening a car door and saying, 'Hi'. I think my dialogue's gone up a bit too." He laughs ruefully at the side effect of higher billing. "I can't have it both ways, can I? There's only so long you can play the silent type standing in the background. GoldenEye was good for that, " he smiles. "I was the villain: James Bond was doing all the heavy lifting. I liked that."

Although Bean has an appetite for work, it came to him only in later life. At school in Sheffield in the sixties and seventies, he says, he was an indifferent student: afterwards he drifted into art college, but his stint there was similarly uninspired.

Therewasn't much available in career terms in the Sheffield of the late seventies, but Bean was lucky: his dad was a welder and had his own firm, so he was taken on as an apprentice.

Yet as he stood there learning a trade amid the showers of sparks and acrid smoke, his heart still wasn't really in it.

"At the time I was interested in music, and I was into punk and new wave and David Bowie - and also literature, " he recalls. "At art college I started to do music, and then painting and drawing - and that would have been my ideal life, to be an artist and be paid for it, to be able to create stuff. I realised it was difficult, but I don't know if I had the application for it.

I mean, I went to college but I didn't really apply myself in terms of the form, the lighting, and all that. I went and drew what I wanted.

That put me in a situation where I knew I wanted to do something different, and I think the combination of music and literature and art that I found in performing encapsulated all that. It combined all those themes in one and I felt very comfortable."

There was, he insists, no Billy Elliot moment. He wasn't a welder one minute and an actor the next. It was a slow process, the gradual stirring of a long-hidden desire - but the time came when he knew he would have to put down the welding mask and head for the bright lights. "I did about three years of a four-year apprentice course as a welder, and I had a good time, " he says. "There were some good guys working there - I learned to grow up around people and get on with people, and I enjoyed working. I was a fabricator, an apprentice plater. I did quite a bit of it and I had some good teachers, but I just wasn't quite suited to that." He chuckles. "I can still weld, though. It might come in handy some day."

Although he makes light of it now, turning his back on the job could not have been an easy decision - and not just because he faced an uncertain future. After all, Bean appears to be as bluff a Yorkshireman as they come. He likes his pint, his women, and his football (perhaps the world's most famous Sheffield United fan, he sports a club tattoo on his shoulder). His was not a world in which it was particularly easy to come out as an actor - especially not a would-be actor.

Bean shifts uncomfortably in his seat.

"There was resentment to some extent - that thing about being a bit of a pansy, you know?"

He laughs nervously and drops his eyes. "It's just not what happened at that time. Sheffield and the outlying areas were industrial, and you went into one trade or another like mining or the steelworks or manufacturing. Not everybody, of course - there were others who wanted to explore different things - but that was the generality. You left school at 16 and went to get a job. You wanted money in your pocket to try to be independent. I had a lot of friends who were builders and plasterers and tradesmen - and I still have." He laughs.

"We've become friends again." In some ways, you suspect, the esteem of former workmates matters more to him than how high his name might appear on a movie poster "So it [acting] just wasn't what you did, " he continues. "I didn't explain it to anyone because I knew what I wanted to do - but it did raise a few eyebrows, including me mam and dad, especially because it was my dad's firm I was working for. There was a certain time when he was dubious and sceptical, but at the same time he and my mum wanted me to achieve what I wanted to do, so there were definitely mixed feelings."

As the father of three daughters - 17-yearold Lorna and 13-year-old Molly, whose mother is the actress Melanie Hill (they divorced in 1997), and six-year-old Evie, whose mother is the actress Abigail Cruttenden (they divorced in 2000) - Bean can now better understand how his own parents felt at the time. He can also relate to their feelings of relief that his career has turned out as it has.

They have seen his work and are naturally proud - after all, what father wouldn't be thrilled to have his son knock seven bells out of James Bond?

"I go to see my kids in school plays, " says Bean, trying to articulate his own parents' emotions. "I watched Lorna in a concert at the Westminster College of Music the other day and it was amazing. I felt very proud - and surprised. I don't know why I was surprised, because I've known her for 17 years, but I've never seen her do anything like that in front of an audience. It's brave, it's uplifting."

Despite his parents' misgivings, Bean was determined to follow his heart. Once he got to London and spent two and a half years at Rada, the Royal Academy of Dramatic Art, he knew he had made the right decision. But he is offhand about his time there - "I had a great time and I learned a lot" - making it sound as though you can simply walk in off the street. In fact, Rada takes only about two dozen hopefuls every year out of some 3,000 applicants. For someone like Bean, with no formal training to speak of, gaining a place there is a remarkable achievement, and a tribute to his raw talent, commitment and enthusiasm for his craft. And in a way that's what's easy to forget about him.

Whether he's a baddie in Bond, a bit of rough in Lady Chatterley's Lover or a dashing soldier in the TV series Sharpe, he is an exceptionally good actor.

He's a big star now but he looks back on his early days with a wistful fondness that suggests he wouldn't mind exchanging the responsibilities of his current status for the carefree days of his youth. Days such as those he spent at the Citizens' Theatre in Glasgow where he was billed as Shaun Bean (his given name - the visually alliterative spelling came later).

There is genuine warmth in his voice as he recalls his earliest days as a professional actor.

"I enjoyed my time there. I worked with a lot of good actors - Ciaran Hinds, Gary Oldman, Lorcan Cranitch. It was about 1983 or 1984, and it was a hot summer in the Gorbals. They had a great green room with a pool table, a bar and a little telly. You'd go in even if you weren't working - it was like a youth club with beer on tap.

"I haven't been up there for a while, but I have great memories of working with Giles Havergal [the former artistic director of the Citizens']. It was very off the wall and exciting.

In theatre, once you've got the character and you've got things together, you can relax into it. Film has a different feel - you don't get that through line of not stopping. Theatre is like a snowball gathering momentum and getting bigger, whereas in film it's a bit stop and start - but you do tend to adjust to that quite easily.

In a big show, like Bond or Lord of the Rings where they take two or three hours to set up a shot, you sit around and read or something, and then switch on again when required. But of course if anyone cocks up, that's it." He shakes his head. "I was watching Goodfellas the other night and there's that tracking shot that goes on and on and you can imagine the fear of some small character cocking it up."

It was this grounding, first in the Gorbals and then, in the 1990s, on Sharpe - a fiveyear series of ITV dramas about a soldier in the Napoleonic Wars - that led Bean to his current status as Hollywood's villain of choice. Whether he's terrorising Pierce Brosnan in GoldenEye, pursuing Brittany Murphy and Michael Douglas in Don't Say a Word, or trapping Nicolas Cage in a ship full of high explosives in National Treasure, Bean is the man the studios go to when they want major villainy. Actors will tell you that any goodlooking fool can be the hero, but it takes real skill to play a villain.

"That's the thing about Brits - they have the grounding in the classics and theatre, " says Bean. "That's why we're good. We go to America and people respect that because we've been through the theatre, we've made discoveries and also made our mistakes there, and that's a wonderful environment to be in.

By the time you start to make television and films you've got some experience behind you, an anchor. All those things, when you put them together, give you a certain amount of confidence and a certain belief in yourself, and the ability to adapt and change to some of the different roles you play. You need to be a good actor to play a villain, and we're always getting cast as villains because we play them well."

Bean says he took the roles in Lord of the Rings (as the warrior Boromir) and Troy (as the hero Odysseus) to prevent him being seen as nothing other than a killer, but he also accepts that playing the villain has got him where he is today. He may grumble about having more dialogue, but the roles are getting more interesting - particularly the part he is playing in The Island.

Directed by Michael "Pearl Harbor" Bay, The Island is a science-fiction thriller about a futuristic closed community where the inhabitants believe they are the only survivors of some unnamed catastrophe that has destroyed society. What they don't know is that they are actually clones of people in the real world, and their purpose is to be harvested for organs. When two characters, played by Ewan McGregor and Scarlett Johansson, discover what is going on, they decide to break out from the island and confront the authorities. Bean plays Merrick, the scientist who runs the institution where the clones are grown. Naturally, he's the bad guy - although Bean is at pains to point out that things aren't quite that simple.

"I suppose you could call him the villain, " he concedes, "but he's a very intelligent guy and wants to further science and help humanity by creating a different world. He's quite sinister in some aspects, but it depends how you feel about that subject, cloning - how you feel about it morally. He believes completely in what he's doing and he believes he's advancing the cause of science. He has this massive complex and it's a big business with the government involved and he has clients who are paying large amounts of money for these 'agnates', as they call them.

"But I think he also believes he's doing good.

He gives lectures where he talks about setting up children's wards and curing cancer, and if you look at it from his point of view then he's trying to eradicate these fatal diseases and rid us of these horrors once and for all."

As the father of three daughters, Bean admits that The Island did force him to take a view. The issue of cloning, he admits, is something that gives him pause for thought - as does so much other modern technology.

When he was a child, he recalls, the biggest scientific advance was the introduction of BBC2 - "Wow, suddenly we have three channels" - which was hardly going to have a serious impact on the future of mankind. Now he has a six-year-old and he has to wonder what the world has in store for her.

"Where does it end?" he asks. "It makes you wonder what you would do if you had a child and she was fatally ill or there was an emergency and she needed a new heart or liver or lungs. What would you do in that situation?

Would you take the life of someone else for the life of your child?" He thinks for a long moment. "It's difficult, isn't it? What would I do? What would they want? When you ask yourself if you have the chance to live for much longer because of the spare parts, would you do it? I don't think I would, but it's up to the individual. I just get the feeling that you never know how it was going to end - if people lived forever, how would that effect the population?"

To be frank, cloning might suit Sean Bean. If he had his own clone then he could do all those films and still get the chance to enjoy that holiday he keeps trying to have. The problem is he keeps on getting offered all these interesting films. How, for instance, could you turn down the chance to work with Jodie Foster? They star together later this year in Flightplan, which sounds like it might well be an intriguing thriller.

"I'm the captain of one of these giant new planes, and 90 per cent of it takes place on board, " explains Bean. "We were just filming in one place every day - the whole crew inside a plane every day - and it's quite laborious having to change round for every shot and working in such a tight space. But when you see it it looks great.

"The idea is that Jodie Foster is with her child and she's going back to New York from Germany with her husband's body. She loses her child on a plane, and you think, 'How can that happen?' There's no record of her having brought a child onto the plane, and the captain is left wondering about whether she's telling the truth. You never really know if she's telling the truth or not."

I confess that when I saw the trailer for Flightplan I immediately had Sean Bean pegged as the kidnapper. "Yes, most people think that, " he says with a wicked smile. "I'll leave you to find out for yourself."

The Island is out on August 12. Flightplan will be released in October.