The great British hope: How Andrea Riseborough took the film world by storm

Andrea Riseborough is telling me a story about the last time she was in Paris. A woman, "who looked like Edith Piaf in the late years", was sitting next to her in a restaurant. "We locked eyes for about five seconds," she explains, a little dramatically, "which, as you know, with a stranger, sitting on the Montparnasse in Paris, is an extraordinarily long time to lock eyes." Within a few seconds, the woman was gone – and so was Riseborough's phone, which had been in her handbag, resting on her lap. "I will never forget her face," she sighs. "And one day I'll play her."

Given, in her five-year career, she's already gone from a young Margaret Thatcher in the television drama The Long Walk To Finchley to a Buzzcocks-obsessed punk in the Sam Taylor-Wood short, Love You More, you can bet transforming into an ageing Parisian pickpocket is not beyond her. But it may have to wait. This last week has been a remarkable one for the 28-year-old. With three movies unveiled at the Toronto Film Festival, the actress from Whitley Bay is being hailed as cinema's most exciting newcomer. Already dubbed the festival's "It girl" by The Hollywood Reporter, pundits are predicting an Oscar nod for her role in Brighton Rock.

A Rowan Joffe remake of the 1947 classic by John Boulting, this new version relocates the action to 1964 and casts Riseborough as Rose, an innocent waitress caught up in a murky underworld of mayhem and murder. Featuring a cast that includes John Hurt, Helen Mirren and Control's Sam Riley as Pinkie, it's Riseborough's performance as a woman starved of affection that has already been heralded as the standout turn, with words like "breathtaking" bandied around. "To say her achievement deserves an Oscar would be somehow to demean it," gushed one critic.

Joffe admits "what Andrea has that many actresses of her generation do not have is a bona fide chameleon-like ability to be totally different from part to part". Indeed, despite those distinct saucer-shaped blue eyes of hers, it's almost impossible to recognise her from one role to the next. To her, such change is just part of the job. "It's really interesting to step into someone else's shoes," she says.

Inevitably, the comparisons have already started. "Is Andrea Riseborough the new Keira Knightley?" blared one British broadsheet recently. Scrub that. What about the new Carey Mulligan? Not unlike Mulligan, who first came to prominence at Sundance when An Education premiered last year, Riseborough owes her own rise to the attention that a North American film festival can bring.

Home-grown audiences on the opening night of this year's London Film Festival (LFF) will get their chance to see her, when Riseborough goes up against Knightley and Mulligan in Never Let Me Go, American director Mark Romanek's adaptation of the novel by Kazuo Ishiguro. With elements of sci-fi mixed with a haunting tale about loss and love, the film has already drawn comparisons to Children of Men for its story of three friends (played, in their adult years, by Knightley, Mulligan and Andrew Garfield) who spent their childhood at an eerie English boarding school.

Riseborough plays Chrissie, one of the group's friends when they hit their thirties. "There were so many attractions," she says, "like the story, which is one of such humanity. The way that it's written and the way hopefully the film will manifest is one that's so subtle, so you form attachments to the characters and you gradually realise the world that they're living in is a parallel universe to the one that we live in."

The cast also includes some of Riseborough's former collaborators – Sally Hawkins, with whom she featured in Mike Leigh's Happy-Go-Lucky, and the newly announced Spider-Man 4 star Garfield, who was at the National Theatre with Riseborough back in 2006 in a trio of plays about London teenagers. So did it feel like she was among the most exciting British actors of their generation? She shakes her head. "You don't think in those terms. But what you do think is: 'Wow, I'm getting to make this with all of my friends.' It's such a rare opportunity. It was lovely that we were all able to work together in that way because so often you are the young thing. Or you're the one female, like I was in the Thatcher film."

Riseborough also stars with Hawkins in Made In Dagenham, her third Toronto-screened effort. Set in 1968, it deals with the true story of what happened at the Ford plant in Dagenham, Essex, where 300 female machine workers walked out in protest when their demand for the same pay as the men was refused. The strike led to the Equal Pay Act in 1970.

While Hawkins plays Rita, the woman at the heart of the tale, Riseborough lends strong support as her colleague Brenda – confident, sexually liberated and the polar opposite of Rose in Brighton Rock. Featuring alongside Jaime Winstone, Rosamund Pike and Miranda Richardson, "it's a female film that will be so enjoyed by men," Riseborough promises. "These women, they're the best – they're so full of charisma."

Directed by Nigel Cole, who made Calendar Girls, she admits there was one overriding reason for joining the project. "It's a very, very interesting story and one really close to my heart." Her grandmother, it transpires, worked in factories for 60 years. "Heavy work. She stopped working in 1980, and only for the last few years of her career did she have equal pay with the guy sitting next to her."

Riseborough's parents worked in factories before her father became a used-car salesman and her mother a secretary. The actress has joked that her parents were "working-class Thatcherites who did well in the 1980s boom". They were able to afford to send Riseborough and her younger sister Laura, also now studying to be an actress, to private school.

"My mum, when she was 50, reignited her own passion [for theatre] that had been dormant, and she went to Open University and she's now Master of Shakespeare and Jacobean studies. And my Dad...his mum was an usherette in a cinema. They'd have two movies in a week, and he'd see the first one three times and the second one four times. Every night after school, he used to sit in the projection box, and his mum would give him ice creams! So he's had a passion for cinema for as long as I can remember. He's so cinema and my mum's so theatre!"

While this may explain her "dual passion" for both art forms, when she was a child, every Sunday afternoon her father took her and her sister to the cinema. "I wouldn't have known about Humphrey Bogart, had it not been for my Dad. He's like my 'phone a friend' on Hollywood films!"

Riseborough says she's had "a relationship with cinema for such an awfully long time" now – everything from the "really elite, only [watching] Tarkovsky for two years" to loving George Lucas and Steven Spielberg epics. As a youngster, whenever she was asked what she wanted to do when she grew up, it would go from being a nuclear physicist one day to a binman the next – early evidence of her chameleon-like traits.

She began acting aged nine and notably playing Miranda in The Tempest when she was just 14. "I've been obsessed with Shakespeare for as long as I can remember," she explains. Already earmarked as a talented dancer and a candidate for Oxbridge, when she was 17, Riseborough demonstrated her rebellious side. Without finishing her A-levels, she quit school, though remains unrepentant even now. "I just didn't want to go to school any more, simple as that."

She left home, getting a series of jobs – including running a Chinese restaurant – to pay the rent. The menial work didn't last long, after her application to Rada was accepted. "I said, 'Mam, you'll never guess who's got into Rada.' And she went, 'No. Who?' I said, 'Me, actually.' Talk about pissing on my chips."

While she speaks with only a faint North-east accent, she still seems very attached to her roots. "The further you creep up North, the palette of the landscape becomes purple and grey, moors and heaths," she says, as if she were auditioning for Wuthering Heights. "And I think that lives in your blood. You can never escape it. I'm always fearful of quaint countryside. I always feel like I'm in Disneyland, because I grew up somewhere so wild. And people are crazy in Newcastle – they don't wear coats! I was always such a crap Geordie. I was out there in my ski-suit. I was like 'It is cold, OK?'"

She graduated from Rada in 2005, and within 12 months was making an impact on stage. She won the Ian Charleson Award, which recognises exceptional classical stage performances from actors under 30, for her dual performances in the title role of Strindberg's Miss Julie and as Isabella in Measure for Measure, both as part of the Peter Hall season at the Theatre Royal Bath.

Since then, she's played Kenneth Branagh's lover in Ivanov and says she has no desire to ditch her stage work now her screen career is taking off. "I find so much pleasure in cinema and theatre, that it would be incredibly hard for me to drop on or the other."

It's on screen that she made her biggest impact. Even before Toronto, there have been some remarkable turns. In Channel 4's four-part TV drama The Devil's Whore, she was glorious as Angelica Fanshawe, a naïve lady-in-waiting at the court of Charles I, who becomes our guide through the English Civil War. There was also the BBC drama Party Animals about young political researchers in which she played the scheming "vixen" Kirsty, who believes "sex can be traded for power".

Then, of course, there was her take on a certain grocer's daughter from Grantham. She spent hours watching footage of Thatcher at the BFI library, reading her autobiography and even visiting her old bedroom in her family home. It evidently paid off. Just listening to Riseborough talk about the role shows her attention to detail.

"Margaret Thatcher beaks her head forward a lot, like a pecking bird," she explains. "So why does she end up with this, gradually, more and more craned neck? It's because she used to tell people what she thought, and then when they didn't get it, she'd tell them again."

Commitment seems a byword for Riseborough – perhaps why, in the past, she's described herself as "the most boring woman in London". She spent seven months on Happy-Go-Lucky, developing the role of Hawkins' flatmate that barely appears on screen – though nevertheless calls the experience "an extraordinary place of privilege". Even on the 2009 film comedy Mad, Sad & Bad, one of the few missteps she's made, she spent time with the director in "therapy sessions" as preparation for her character, an unconventional artist.

"The great thing about being an actor is...you can read a script and sometimes it can be totally exhausting, because you act all the parts, accidentally, in your brain," she says. "In fact, often, I know when I read a really good script and the part is fantastic, then I'm only that part through the whole thing. But it can be quite funny, whether you operate like that naturally. I can remember as a child, watching the news and getting really upset."

So she's someone with a great deal of empathy? "Look. For me to say I have a lot of empathy would be like a huge complement to myself, and I cannot be that judge. It would have to be someone else who said that. But don't we all strive for empathy?"

Now dividing her time between London and Los Angeles, where she rents a place, there will come a point where she may find it hard to resist the call of Hollywood, especially as Lady Luck seems on her side right now. When Carey Mulligan was forced to pull out of Brighton Rock, Riseborough stepped in. Likewise, when a pregnant Vera Farmiga dropped out of Madonna's forthcoming directorial debutW.E, Riseborough was called upon to play Wallis Simpson, the American divorcee noted for the affair that led to the abdication of Edward VIII. Madonna, according to producer Colin Vaines, was "amazed at how Andrea can go across the full range", playing a role that spans some 40 years.

Both these roles promise to give her an even bigger platform than Made In Dagenham and Never Let Me Go. The only problem is, Riseborough has barely had a day off since Rada, as she is in such demand.

Is she concerned that she's working too hard? "It's not like I actively worry about it," she shrugs. "You're just doing the job. And because you love what you do, and you're enjoying doing it, it's sometimes hard to monitor yourself. It's not easy to step outside and go: 'This is really bad, I shouldn't be doing it,' because it feels so right."

'Made in Dagenham' opens on 1 October. 'Never Let Me Go' opens the BFI London Film Festival on 13 October and goes on general release in January. 'Brighton Rock' opens in February 2011