She's just a girl who can say no. After years of doing the right thing, Saskia Reeves is holding out for the right parts. Interview by Ryan Gilbey

When Saskia Reeves first experienced repertory theatre - a margin into which she had promised herself she would never stray - it turned out to be everything she had dreaded. Hired at the 11th hour to play in a production of Faust in Clywd, she sat in her dressing room in the grim winter cold and thought, "If this is what it's about, I ain't doing it. I don't want to do rep. I'm miserable. I'm lonely. Nobody likes me." Lounging in a bright loft office in London on a summer morning, she laughs at the self-pity that absorbed her back then. Her years at the Guildhall drama school hadn't been much easier.

"They didn't think much of me there," she says, relishing the irony. It might seem like arrogance but her derision is rooted in a deep and concerned mistrust of drama schools. Her own experiences have made her fear for those negotiating the system.

"I do worry," she insists, "because schools have a lot to answer for. 'Take any job you can get,' they say. No! Don't take any job you can get. There are a lot of horrible people out there. No. Do what you want to do. Don't do The Bill if what you really want to do is puppet theatre." She sits back calmly, her outburst leaving the air crackling.

"Actually," she confides, "my first job was doing puppet shows and pub theatre. A nightmare. But it got me an Equity card."

Then came the obligatory bout of waitressing, and a pressing letter from the DHSS insisting she come in for some career advice. Then along came Faust and she sold her soul to theatre.

In the decade which has elapsed since then, that person who sat staring at her dressing room walls, despondent and despairing, has done stints with Cheek By Jowl and the RSC; she has worked with Britain's most challenging theatre directors - Steven Berkoff, Mike Leigh, Max Stafford-Clark; and in the past six years, she has carved out a film career which has shown her to be one of the country's freshest and most startling talents. Yet she remains more fan than star: just recounting her meeting with Harvey Keitel at the Berlin Film Festival makes her eyes widen in disbelief.

The memory of the 1991 incest drama Close My Eyes, the film which truly heralded her arrival, has a similar effect on you. If you saw her as the wilfully destructive sister to Clive Owen's bewildered brother, you won't have forgotten the urgency of her performance. "Stop me," she whispered memorably as she stripped Owen bare and wrapped herself around him - "Stop me." Those words were ripe with a longing and lust and terror that other actresses would need a two-page monologue to convey. Her fearlessness made her stand off the screen like braille; it was a consummate Saskia Reeves moment.

It was also a plainly controversial role to plump for, though it seems tame by comparison to her latest, Butterfly Kiss, in which she plays Miriam, the dowdy lover of Eunice, a babbling psychopath played by Amanda Plummer. Reeves shares explicit sex scenes with her co-star. She also gets to club a chap to death (though that's not nearly as shocking as her gruesome perm). Such matters are incidental as far as she's concerned.

"I don't go looking for controversy," she maintains. "I just think of who I'll be working with. I'd think twice about taking on an enormous part like Miriam with a director that I didn't feel would be there for me. I realise that it isn't just what you do during shooting that counts. In fact, the film doesn't really begin until the director and editor take it away. So you need to know that the people you're providing the pieces for will make a good picture from it."

Ever been shocked by the results?

She thinks for a moment, her eyes searching the corners of the room. "I've been disappointed. And saddened. Not shocked. Not yet."

Although Reeves is quick to play down her exhaustive methods of research - "I don't want to sound like Robert De Niro" - you can't help but admire her dedication. The donkeywork behind her portrayal of Miriam comes from various sources.

"Part of her is a girl I knew at school, Frania Ryski, who had no neck."

Frania is mulled over for a second. "Lovely girl. But literally like this," she says, hunching her shoulders. She also interviewed a group of deaf children once she had decided that Miriam would wear a hearing aid. When she was preparing to play a brash barmaid in the thriller I.D., she hung around the East End, observing, collecting, absorbing. Is there an attraction in leaving your own life so far behind?

"Oh definitely, because you've got further to go. It becomes even more interesting if you have to travel to another job, another class. I'd shy away from playing an actress who lives in London."

Is that what taking risks means for you? "Taking risks for me means saying no to things. Holding out for work that I really want to do because I never know if I've done the right thing. Those are the risks I've taken, and in the process I've turned down very respectable work that would have taken my career in a completely different direction. And I know a lot of people who have thought, 'You're absolutely mad.' I don't expect any sympathy, it would be like 'Oh, poor you, what a tough decision, should I work with this one, or the other one?' I'm very aware of sounding spoilt."

She's only learnt to be so selective in the past year, to the extent that she is now sniffing out smaller parts, like the one in I.D. and the upcoming Crossing the Border.

"The thing I hate about film is the concentrated period of working like a horse then suddenly stopping, like running really fast and smashing into a brick wall. I'm getting sick of it. It makes me feel like I don't know what I'm doing anymore, and then I start thinking about giving it all up."

What stops you?

"Well I've started thinking about what I can do other than acting, and that excites me. I haven't worked out what yet. I want to direct. I want to do more theatre. The process is so warm, so human. When I was with the RSC, I didn't have a night off for eight months, and you don't really have to be that good because it's all practice."

She has other ideas crowding inside her too: directing; sculpting; enrolling in film school in New York. I tell her she sounds like she feels unstoppable.

"I feel like I've only just started," she replies, splitting open an orange and wearing the mischievous grin of someone who knows they need never say yes to Faust in Clywd again.