John Walsh meets Kerry Fox... the `Shallow Grave' star who gets what she wants
Art-house moviegoers who have seen Jane Campion's ground-breaking film An Angel at My Table will remember the heroine with awful clarity: an unprepossessing, fat pubescent with an off-putting frizz of orange hair and a nasty cardigan, trying to conquer her many social disabilities and become the writer Janet Frame. Fans of Trainspotting who have checked out its producer-director team's earlier work, Shallow Grave, may recall, of the three Glasgow flatmates who bury Keith Allen's dismembered body, the woman called Juliet, who flashes her tits at the camera with splendid unconcern, gets beaten up by avenging thugs and tries to abscond with the money at the end. And television viewers with a fondness for Joanna Trollope's novels surely cannot forget the squire's lesbian daughter, Clodagh, in A Village Affair (ITV, Easter 1995) who seduces the sweet young bourgeoise played by Sophie Ward, one hot afternoon after she's put the baby off to sleep. Extraordinary to think that all three characters - the shy gawk, the cool ghoul, the sapphic siren - should all have been played by the young women sitting beside me in the empty Circle Bar of the Donmar Warehouse theatre, Covent Garden.

Kerry Fox is 30, a New Zealander now living in London after years of traversing the globe, chasing work from Australia to Bosnia by way of South Africa and the Philippines. She is blithely insouciant about this restless travelling, as if boxing the hemispheres were a perfectly normal way for a busy young actress to live. Tall and solidly-built, she radiates intelligent self-confidence, with occasional whinnies of incomprehension at one's more pretentious lines of questioning. She is, as everyone points out, neither pretty nor plain but can suggest a creamy sexiness or a threatening nullity just by turning her head. It's all to do with the eyes, which are her best feature. In repose, they're large and unblinking; on celluloid, they can flash with a cold, Lamia-like snakiness or smoulder with calculation.

Ms Fox and Niamh Cusack are currently packing the Donmar stalls for their joint impersonation of The Maids in Jean Genet's perverse, mercurial play of that name. Every night, Solange (Fox) and Claire (Cusack) shed their servile encumbrances to act out a series of traumatic relationships - master-slave, mother-child, monster-victim - until the game turns sour and they resolve to kill their worldly employer, played by the gorgeous black actress Josette Simon in figure-hugging haute couture. The role of Solange gives Ms Fox a chance to move through a succession of wildly shifting emotional extremes. She can be droopily submissive one moment, and frighteningly belligerent the next, then pathetic and crumpled, then businesslike and homicidal. It is, amazingly, her first-ever appearance on a British stage.

Did she feel that (unlike most critics) she understood what Genet was on about? "I think a lot of people come to the play with preconceived notions, mostly because they're stuck on Sartre's essay, where he says the play was written for men. It just wasn't. Genet turned round after Sartre had written a whole chapter about his theory, and said, `I never said that.' It's all a myth. But if people come to see it without expectations, they start to see similarities with their own lives and what they've done to other people."

She admits to feeling "completely knackered" after eight performances a week of this shape-changing melodrama in which all the characters are acting other characters all the time. "Often when I'm playing a part, I have an image in my head of what the character's like, I have a picture of her and try to adapt myself to fit it. But in The Maids, I had to toss that way of working right out the window. Here, everything comes from the other actor. Whatever you're doing is a direct response to what they've just done. My performance is defined the moment Niamh opens the door [to enter the bedroom, at the beginning of the play]."

She has theories about the characters and their interchangeability, their way of turning into each other and confusing whom they're talking to. Didn't it drive her mad, all this blurring of identities? "Well you're obviously baffled about how to take it," says Ms Fox severely. "It's a matter of what seems real to different people. When I've spoken to people in the past who've had delusions, their delusions are very logical and make complete sense". Had she researched the role? "Only to the extent of reading Genet." She hadn't fancied becoming a parlourmaid for a fortnight? "No. In fact, I kept thinking, I don't know anyone like these women. You just have an image from the TV about how maids should act. But we didn't want to get into that area, that class business."

Being from New Zealand helps, she thinks, to suggest an undercurrent of colonial oppression in the play, as does Niamh Cusack's Irishness. The actresses have clearly become very close, in rehearsing their nightly battles for mastery. "We share a dressing room, so it's very easy to talk about things, if we think something's missing or something's wrong. And we have some wine after each performance and talk about how it went. And there's the accents..." Accents? "Well you wouldn't have noticed," she says, "but we've tried to merge our two accents. Niamh tried to flatten her Irish accent to become more like mine and say `bid' instead of `bed', and I've added some of her rhythms, so I say `Clairrre' rather than `Clai'..." And what gets picked out in the reviews? "How New Zealand I sound..." She was originally turned down for the role by the director, John Crowley. "He didn't want to cast me because he thought I was too young. So I had to convince him. I said, how could I possibly be too young, that it was up to me and Niamh to play it as if I was older... And in the end he had to cast me." She lights a cigarette calmly. "You've got to make other people believe in you. You have to say if you really want something."

It's been a curious flight path that's landed this persuasive Kiwi in Covent Garden. She was born in Stubbs Valley, a suburb of Wellington, New Zealand. "Did you see Heavenly Creatures? [the movie set in Christchurch, NZ, in the Sixties, in which two schoolgirls murder one of their mother's against an atmosphere of stifling ennui]. It was just like that. I grew up in complete suburbia, a quarter acre of it, surrounded by the bush. There were hills in the background. We could walk to school without any fear of danger." Her family was "very straightforward", her father an accountant for a firm of kitchenware exporters. "He had strong views about behaviour. He'd never shout at anyone, never swear or hit us. He understood that people make mistakes all the time. And he'd avoid confrontation, which is a very New Zealand trait..." The youngest of four children in a family characterised by shyness, Kerry stuck out as a noisy show-off. "My father told me later, after I'd been to drama school, that I was the bossiest person he'd ever met, and the most aggressive - and I think that stubbornness, and always thinking I'm right, is probably both my best and worst feature." (Kerry, in case you're wondering, was not in Heavenly Creatures. She was, she says, "too old" and no amount of actorly rhetoric could change that).

After being involved in drama groups at school, she dropped out of university and embraced the New Zealand Drama School with rapture. "It changed everything. It was like the opening of my life. That's why I related so much to Janet Frame in An Angel, as she finds out she's a writer. I'd done a lot of acting before - but to be with a group of people who spoke the same language as you, and wanted to understand about people in the same way..." She left, tried stage management, acted in fringe productions, did an ad for the New Zealand Listener ("like your Radio Times") and "some terrible auditions" for theatre directors. The prevailing smallness of post-college life might have killed her spirit. But then she read the script of An Angel at my Table - "and I knew I could do it, and that I'd have to do a really good job, because if I didn't, it would mean I'd just been wasting my time." Thus Ms Fox sprang, virtually fully-formed, from drama school into moviedom without any of the usual decent interval of juvenile roles in provincial towns followed by crap television sitcoms.

Angel was filmed in New Zealand. It, Jane Campion and Ms Fox were loudly praised - but Kerry got no work for for a year, as casting directors failed to see beneath the marmalade frizz she'd worn to play Janet Frame. She was rescued by another Antipodean woman director, Gillian (My Brilliant Career) Armstrong, who put her in The Last Days of Chez Nous, filmed in Australia, then by Elaine Procter who gave her the lead in Friends, a hand-wringing little drama about interracial loyalties, set in South Africa. "Nelson Mandela was out of prison, though not in power, at the time, so the film was already dated when it came out," she says. "I thought some of South Africa was gorgeous, but the people - the way they speak to other people... If they introduced someone, it would be, `This is so-and-so, his background's Jewish and his family came here in 1947...' There's this baggage of family trees, so people can't relate to each other immediately and directly."

Kerry Fox's big break, however, was meeting Danny Boyle, the Mancunian director. They met in London at her agent's office. Boyle was auditioning actresses for Mr Wroe's Virgins, the television version of Jane Rogers' novel about a 19th century preacher with a seraglio of querulous maids. "I knew the one I wanted to play, of the four girls, but he didn't want to offer me it. I said, `I'm not going to play any of the others.' Eventually, I went back to Australia - and later, he offered me the part I wanted." How did she get her own way? "By being utterly convinced I'm right."

Boyle called her up when he moved on to direct Shallow Grave. "When I read the script, I thought, `I don't wanna do this, it's gratuitously violent,' " she says with distaste. "But at least we tried to make the violence real, not dress it up in stunts, going `biff!' and `whack!'." I recalled a moment in the film when Ewan McGregor drunkenly sprawls on the floor of a restaurant, with Kerry Fox's shoe grinding into his face, and the camera (shooting from below) captures a snarl of sadism on hers. There's a coincidental echo in The Maids, when her character kneels to kiss Niamh Cusack's shoe. Was she drawn towards perversity? There was a long silence. "I'm drawn to oppression and trying to understand how people can be so cruel to each other. I'm trying to expose cruelty, not allow it to be explained away in some mystical fashion..."

She will next be seen on screen in Welcome to Sarajevo (to be released in November), Michael Winterbottom's moving record of siege conditions in the Bosnian town, as it was bombed and shot at by its neighbours. "It's shocking about how destructive and violent people can be, but it doesn't glamorise it the way Hollywood likes to. It's more honest." She plays a television producer in the war zone, "who starts out kind of naive and desperately trying to do the right thing, and has to toughen up, and ends up very bitter and twisted. But the best thing about making the film was watching Stephen Dillane, who plays a war journalist and is really amazing." Fox and the crew spent a fortnight in Bosnia just days after a wobbly ceasefire was declared. "It was easy to imagine what it must have been like - this really groovy cafe society. The women were incredible, so big and tall and elegant, while the men just sat around in cafes all day with their kids. You could see the women really ran the show." She sighed. "That's why it's so horrific to see it so devastated."

Meeting the Sarajevans wasn't an entirely happy convergence of moneyed western and war-torn eastern Europe. "Most people paid no attention to us at all. They had far more important things to concern themselves with than a movie. And it's hard to ask people from a war the kind of things you'd like to ask - like `Did you kill anyone?'. But people wanted the film to be honest about their horrific personal experiences. They wanted the world to understand, so, yeah, they talked to us and told us all the terrible stories..."

Ms Fox's feline eyes flash briefly. For a moment, her chronic diffidence, and her breezy self-confidence about getting what she wants, are invaded by a moment of genuine human sympathy. After 10 years of impersonating awkward misfits, schemers, virgins, seducers, bruised neurotics, embittered media types and murderous domestics, she sounds like she could do with a break from inspecting human misery and cruelty. Is there a comedy out there someone could offer her?

`The Maids' is at the Donmar Warehouse, London WC2, to 9 Aug (Booking: 0171-369 1732)