Samantha Morton: Morton combat

British actress Samantha Morton has stunned audiences with her bare-it-all performances and has Hollywood falling at her feet. But, says Charlotte O'Sullivan, she's far too good for them

Samantha Morton's hair is draped, Rapunzel-like, around her shoulders, and I feel duty-bound to compliment her on its lustre. The 26-year-old actress is aghast. "No way! These are very bad extensions. Well," rueful sucking in of breath, "not that bad. They're bad 'cos I'm not looking after them properly. Go on, feel!" Morton (eye-catching in miniskirt and cowboy boots) bows her head and jabs at the offending area. Somewhat gingerly, I give it a rub, and agree that the sensation is not entirely pleasant (the points where the real hair meets false feel like little tumours). "Yeah!" she cackles, "the back of my head's like an abacus!"

Most stars don't go in for the hands-on treatment. Woody Allen, for example (who directed Morton to an Oscar nomination on Sweet and Lowdown), makes clear that if he's touched by an interviewer, he'll bolt. I think of these celebrities as old-school museums; the exhibits roped off or behind glass cases. Nottingham-born Morton, by contrast, is all bright lights and interactive buttons. Four years ago, when she was pregnant with her daughter Esme (by actor Charlie Creed-Miles, from whom she's now separated) she whipped up her skirt during an interview with The Independent so she could show off her brand new tummy.

So how to explain the fact that - on occasion - she can also be one of the cagiest of interviewees? It's easily done. She's been man-handled in the past, most notably when an interview she gave about her parents' divorce - and her time spent in foster care - became tabloid fodder. She wants to protect Esme from that kind of chaos. She wants to protect herself. It doesn't come naturally, though. As we wait for our lunch, sat in the garden of her favourite Camden pub, she points towards one of the top-floor windows. "My boyfriend lives there. Can you see? That's his bike."

Morton's performances are similarly designed to haul you up close. She was hypnotically raw in one of her first British film features, 1997's Under the Skin, as a girl who drowns herself in anonymous sex to cope with her mother's death. In last year's cult hit, Morvern Callar, she chops up her boyfriend's corpse, gets drunk, goes clubbing in Spain; and keeps you in touch with her slowly thawing anguish throughout.

In between, Morton found time to shoot off to America, picking perfect roles, in small films and large; an optimistic, deaf mute in Sweet and Lowdown; a sensual junkie in Jesus' Son, and the "pre-cog" who saves Tom Cruise's life in Steven Spielberg's Minority Report (adorable and desperate and blue-eyed, she's the best thing in it - ET made flesh).

Many of these parts have been surrounded by Oscar buzz. And it seems almost certain that she'll be nominated for her latest film. In Jim Sheridan's In America, her character, Sarah, is an Irish Catholic mother of three, whose son, Frankie, has just died of cancer. When Sarah and her emotionally numb husband Johnny (the brilliant Paddy Considine) move to a dilapidated New York apartment, she struggles against jealousy. Watching Johnny play blind-man's-buff with their two daughters, she croons sadly, "What about me?" Blankly nourishing with the little girls, she only comes to life with their strange new neighbour, Mateo (Djimon Hounsou), but even he can't keep her misery at bay. Just after she's delivered a premature child, she whispers to her husband, "If my baby dies, don't wake me up." The film gets positively gloopy at the end; for the most part, though, it's simply and intelligently moving - a light-footed epic that's less Angela's Ashes, more Y Tu Mamá También.

Morton, by now tucking into a pie, asks several times if I liked the film. She bats away Sheridan's suggestion that she'll win an Oscar ("I've been told that so many times, and it never happens. The studio has to campaign for you and it takes so much money and Searchlight [the company behind the film] really don't have much to spend.")

She is a bit worried that the poster (which shows one of the little girls, with angel wings) sends a soppy message. When I say I had a problem with the film's with-one-leap-they-were-free-from-financial-worries ending, she murmurs sympathetically, "Did that seem a bit corny, a bit [she puts on a Vaudeville voice] waa, waa, waa?"

She's a harsh critic when it comes to her own films. "That was one of my problems with Minority Report. Everything was tied up too nicely. That ending, it was too much for me." But she says she didn't have a problem with the stroke of good fortune that gets Sarah and Johnny out of hot water. "I've been in places that are very low," she says, chewing her lip, "and I've really, really prayed very hard that things are gonna turn around and it has, so I kind of believed it. That you can be in the worst shit ever, and if you're a good person, and you're not feeling too sorry for yourself, things can ..."

She trails off, possibly because I'm looking a little incredulous. In America is partly autobiographical. Jim Sheridan's brother, Frankie, died of cancer as a kid; Sheridan himself, as a young man, brought his family to New York, got into debt and they had a premature baby. Things turned out OK for him. Things have turned out pretty good for Morton. But surely she can't believe that every cloud has a silver lining. Or, an even worse Hollywood cliché, that good things happen to good people?

I content myself with saying that Lynne Ramsay, Morvern Callar's director and Morton's great friend, would never have had an ending f like that. She replies, cautiously, that Sheridan has made a lot of films, and Ramsay hasn't. "I'm not saying Lynne will become a film-maker like Jim," she says quickly, "but everyone's got their weaknesses, and strengths. Jim's more of an emotional conductor ..."

She says the shoot was a very cathartic one, that obviously the subject was very close to Jim, but that it was a "funny time" for her and Considine, too. She explains that, just before the shoot started in Ireland, Considine's father died. Then she was told that her stepfather had died.

I ask if she was close to her stepfather. And she pulls a face. "Well, um, it transpires that ... apparently he's not dead. But I ... it was all a misunderstanding of weirdness, but I got a phone call from my mum saying, 'Ooh, Frank's died.' And I was like, 'Oh my God ...' And I was close to him, [she wrinkles her nose] in a funny way. And then afterwards, I was told he wasn't dead. But we still don't know."

She looks up at me and says that probably sounds mad. I say it sounds like a magical-realist novel and she brightens. "Life does imitate art. After Under the Skin, my foster mother died of cancer. I'd just played someone whose mother had died of cancer - well, a brain tumour ..." She wriggles in her seat, with a strange mixture of excitement and distress. Did she like her foster mum? "Did I like her? I loved her. Greatly. She was my mum."

An awkward silence descends - clearly, the interview is creeping into forbidden territory. She has reason to be suspicious. Age 16 - after an attention-grabbing turn as teen a prostitute in ITV's Band of Gold - she was offered £60,000 by The Sun to talk about her rocky childhood. Morton told The Sun to "fuck off". But then was "manipulated" into telling her side of things, and decided The Guardian's women's pages would be a good place to do it.

In the interview, she talked about her parents splitting up when she was three, her dad's affair with a 15-year-old neighbour (whom he eventually married), and how she and her two siblings had been placed in foster care. She says it was like a therapy session - she'd never talked about her past before - and that though she did say most of the things, it was written up "oddly". The Guardian went on to sell the story to all the tabloid newspapers. "At the bottom of each piece you'd get 'Copyright Guardian' and I was like, 'You fucking arses.'"

The paper made money, and Morton's family paid the price. The tabloids arrived in Morton's home town, hoping to get more juicy details, and the pressure was so great that her mother (her biological mother) took an overdose.

Luckily her mother is still alive, but for Morton the sense of betrayal is as strong as ever. As a journalist, it's hard to be self-righteous - just by retelling this story, I'm reintroducing it into the public domain. She wants me to know why she's often forced to be cautious with the press. But, in being so honest about her fears, she's in danger of exposing herself all over again.

She says that even now, she still gets fooled. Morton recently did an interview with i-D magazine. (Morton loves fashion and had just starred in a Marc Jacobs ad campaign, shot by Juergen Teller.) The journalist asked her about the Sex Pistols T-shirt she wore to the Oscars, and the rumour that she'd had "leaky tits" at the Baftas. Morton carefully explained that Esme was tiny at the time, that she was still breast-feeding, then decided this really wasn't something worth talking about. The resulting headline: "I went to the Oscars With Leaky Tits." She says sadly, "He'd got the stories all mixed up. I was like, 'Oh, come on mate, I know you're trying to get an angle, but that's not very respectful.' "

She looks thoughtful. "But I won't become too cynical about it. I was talking to my boyfriend about this - saying how at the end of the day, you just have to not let it ruin your innocence."

So how did she feel about doing this interview? After a number of false starts, she says, "I came here today hoping to say to people, 'Have faith, we've not all sold out.' This is not me saying to the audience, 'Please like me.' I just want them to see someone who is reaching out to them and saying, 'This is me.' " For some, of course, such soul-baring may seem distasteful, even disingenuous. And lots of people, particularly in the British film industry, don't like Morton's style - find her "difficult", self-righteous, overly political and, most of all, disloyal. They don't mind her slagging off the press - but when she starts in on, say, the Baftas (she thinks most of the members just vote for their friends), that's a different story.

I think this is a misreading of her character. For starters, she does own up to insecurities and "weaknesses". She's also obsessed with collaboration. Most of all, though, I think her willingness to criticise others has sound roots. For her, diplomacy is a nice word for being two-faced. Morton is determined to come as close to the truth (or at least, what she perceives to be the truth) as possible.

The next film of Morton's we'll see is Michael Winterbottom's Code 46. It's a love story, set in the future, and co-stars Tim Robbins. The latter is famous for his left-wing politics, and you'd imagine he and Morton were made for each other. Au contraire. When I inquire if Code 46 was everything she wanted it to be, she struggles to say only nice things (she adores Winterbottom), then blurts out, "My relationship with Tim Robbins was pretty bad."

I say I'm astonished, because Susan Sarandon (his partner) seems so impressive. "Well," she says slowly, "we have this association, through her public image, but it doesn't necessarily mean that the man is as the woman is." She makes a face. Was he nasty to her, or did she see him being nasty to others? A long pause. f "It was more that the way we both act didn't click. What that's created is an amazing tension on screen. But um," she says stiffly, "on set, sometimes there's just a wrong cog. Tim's so different from the way we all are. I don't think he'd done his research into how Michael shoots and so he was unhappy creatively."

She can't hold herself in any longer. "When I've gone into environments that I don't personally find as suited to me as others, I've adapted. But I think Tim's quite set in his ways." She giggles. "It's like putting Helena Bonham Carter in a Harmony Korine film."

There are plenty of other people who fail to live up to her standards - Catherine Zeta Jones, for example, whose success she cannot understand. "Did you see her in Traffic? She wasn't very good in it. The film was just great around her." In the same mood, she tells me that Billy Bob Thornton was at one point offered the part of Johnny in In America. "What do you think of that?" I mumble that I think he's quite a good actor and she looks incredulous. "He's too old."

At the same time, she can be very generous. She mentions that she was asked to play Iris in the Richard Eyre film, that she turned it down "for personal reasons". "But then Kate [Winslet] did it, and she was just brilliant, and now I can't imagine anyone else as Iris."

She'd like to be offered more parts in British movies, but says she's rarely considered. "I was interested in that Working Title film [Love Actually]" she says. "I thought doing a mainstream rom-com would be fun. But they wouldn't send me a script, and they didn't want me to audition. They wanted the usual suspects. They got Martine McCutcheon and Keira Knightley. And I was like OK, OK."

Maybe it's her reputation for gobbiness that means she generally misses out on such roles. Or maybe she's just not pretty-pretty enough. Either way, I don't think she's too badly off. Adored by big-name international directors and auteurs, she probably benefits from not being part of the Brit-pic scrum.

Occasionally, of course, she does get wooed and won. Right now, for example, she's shooting Roger Michell's Enduring Love (hence the much-despised extensions), an adaptation of the Ian McEwan novel, alongside Daniel Craig. It's the first film she's done this year (she often turns down work abroad because she doesn't want to be away from Esme).

For her own part, Morton can barely contain her excitement at the prospect of directing her own short film this December. She credits Lynne Ramsay as her inspiration and says she loves Ramsay's short film, Gasman. Her own film is based on something she wrote three years ago, which she's "chickened out" of directing a number of times, "because all my insecurities came out and I just thought, 'You twat, who do you think you are.' "

She suspects her foray into directing will be a one-off: "It's more an art piece - and I resent myself for saying that - but it's true, I'd be more than happy to show it in a gallery." Directing isn't a new departure, she insists. "When I was 16 I wrote a play and staged it. I think that's always been a part of me. Wanting to get the feel right; having an opinion about everything."

By this point, Morton has finished her pie. She's also finished off my salad ("Ooh, look at me," she says with a full mouth, "rabbit Morton"). She won't have pudding, though, because she's got to lose two stone for a film she's making in January, about a girl who's been living in the New Zealand bush for nine years. "Right now," she says, clasping a sturdy thigh, "I do not look like I've been living on berries."

At this point, a car pulls up, ready to take her into Soho, where she's doing a commentary for the Morvern Callar DVD. She orders another cup of coffee and says, "Can I have your opinion?" She's just bought a new hat, and wants to know if it looks OK. I say it does, but that she looks a little like Emily Watson in Breaking The Waves. Morton, grinning, snatches the hat off, and stuffs it back in her bag.

She offers me a lift into town. In the car, she changes the station to Xfm, pulls out some hand cream and asks if I want a squirt. We talk about Halloween (which figures prominently in In America). Last year, some kids pelted the smiling pumpkins she'd put outside her house, frightening Esme, so Morton had a go at them.

I ask what she's doing this year and she shakes her head, distractedly. "This'll tell you something about the weird energy of my street. Last night this woman rang on my doorbell, blood streaming down her arms. She was a self-harmer - she'd made the cuts. So I rang for an ambulance and the woman sat on the step and then they came and she was saying, 'You'll help me with this,' pointing to her arms, 'but who's gonna help me with this?' tapping her head."

Morton's face crumples at this memory. "I can't get that out of my mind. Why don't we take care of people better?"

A project she hopes to develop soon is based on a newspaper article about two Nottingham prostitutes. Morton drops her voice, as if handling something very precious and delicate. She says the article was called "The Unloved".

Earlier, talking about In America, Morton said she was pleased to do it because it's about love and family - about people who don't walk out when the going gets tough. She says this reflects her own life, which is "incredibly together now". I'm sure it is. But I think what gives her - and her work - such gravitational pull is that she hasn't forgotten what it's like to be outside that charmed circle. She knows she can't invite everybody in. But she would if she could.

'In America' is released on 7 November