Jaime Winstone admits that her acting roles to date have required “a lot of screaming”. She has been hedonistic jailbait (Kidulthood), a blood-craving psycho (Daddy’s Girl), caught up in a zombie outbreak (Dead Set), and, in last year’s Donkey Punch, trapped in a murderous spiral after taking part in a fatal orgy during a Spanish beach holiday. She’s also done “some telly” and a couple of music videos. And now, as of last Thursday, she’s in her first play.

In Philip Ridley’s The Fastest Clock in the Universe, there is a character called Sherbet Gravel, “a 17-year-old, pregnant, ex-crystal meth dealer who is completely from a gang”, Winstone explains. It was a part that was just right for her, she says. Before our meeting, I’d always assumed that there was a sort of hardness to the 24-year-old — all fags, drastic make-up and East End savvy, but in reality there is no such thing. At 5ft nothing she’s tiny, made smaller by the black walls and seats in the Hampstead Theatre rehearsal room where she sits in faded silver Dr Martens boots, tight faded jeans and doll-sized black jacket. She is open, funny and, with three days until her stage debut, a little antsy.

“I never went to drama school, never went to stage school,” she says. “I mean, I did drama in school, but it was being-a-seed-growing-into-a-tree sort of stuff. When I first started here, it was learning all about breathing, about projection, about how to carry yourself on stage ... things I was never taught to do. You’re giving 100 per cent — not 30 per cent and getting away with it — so the days feel painfully long. You can’t go home and think, right, drinkypoos! It’s been like a nine-to-five job.”

Her last such job was working in a department store for Estée Lauder cosmetics. “But I got completely sacked!” she hoots. Completely sacked? “Completely sacked, hahaha! It wasn’t my thing, babe,” she says, flicking a limp wrist. Getting older women to believe they looked ravishing was, “in a weird way, my acting training”, she decides once she’s stopped laughing. Soon after, in 2004, she was cast as an unknown in Bullet Boy, a gritty urban morality tale. Or, rather, as a relative unknown. Her father is Ray Winstone — “and I always get the ‘Are you going into acting because your dad was in acting?’ Well, yeah, I am actually.” She grew up with him first on a North London estate and then, as his career blossomed, in comfortable Essex. Her family’s roots, though, are in East London, which goes some way towards explaining the connection she felt with Ridley’s The Fastest Clock in the Universe.

Ridley has lived in Bethnal Green all his life. He is variously a writer of screenplays, adult and children’s books, a director, a photographer and a composer. His plays in particular have a reputation for a pungent strain of East End macabre — sex, death, deceit, brutality and black humour, all within hearing of Bow Bells. (He is “turned on by his own sick fantasies” muttered one reviewer, responding to Ridley’s 2005 play Mercury Fur.) “The play is about clinging on to youth and lust and touches slightly on paedophilia,” Winstone says of The Fastest Clock in the Universe. “It’s very dark, but if you’re aware of Philip’s work, it’s usually very dark and twisted and beautiful all in one breath. Some of the lines that come out of Sherbet’s mouth are quite shocking, but she says them so easily.”

In a blink, her eyes glaze, her mouth tightens and she recites one of Sherbet Gravel’s lines with a jagged bounce: “I bet you could put a bird through a mangle feet first, and the look on its face wouldn’t change one jot.” She snaps back into Winstone and shakes her head. “But then you visualise that, and it’s f***ed up!”

She has, she explains, had to morph into the role of Gravel, becoming her as much as is practical “without actually being a pregnant crystal meth dealer. We’re so different, the only thing in common is the way we sometimes talk,” she says. “You’re toying with your emotions constantly, and the line between Jaime and Sherbet disappears. You start to handle things in certain ways and you think, hmm ... that’s how Sherbet would have handled that. She’s very controlling in what seems a nice, but is actually a quite dangerous, way. We [she and her actor boyfriend, Alfie Allen, Lily Allen’s younger brother] were in a restaurant ordering food, and I started saying, ‘I want this, babe ... I want that, babe ... you want that, don’t you, babe? Yeah you do . . .’ She’s very confident, very relaxed and obviously been in a lot of situations where she has to be in control.”

Ridley himself enthuses about Winstone’s ability to understand her characters. “Jaime is always striking a very clear chime of emotional truth. Watch her in any of her film roles, and she’s so natural and in the moment. She has this visceral instinct and is just able to become those characters,” he tells me. This doesn’t sound gushy or pretentious when he says it, and it isn’t. Watching Winstone act, you always go along with her. You are behind her because whoever she’s playing always feels more like a person than a part; she seems, always, very real. “It’s because she roots everything very firmly back to her life, what she’s seen and experienced,” Ridley explains. “And I write in a similar way, about things I’ve observed [in the East End]. On the first day of rehearsals, one of the first things she said to me was, ‘I know girls just like this’. I said, yeah ... so do I.”

The other appealing, endearing thing about Winstone is that she seems good fun. This year I was at a recording of Later ... with Jools Holland where she, her boyfriend and a posse of glammed-up chums were having what looked like the time of their lives while Lily Allen performed on the show. I tell her that it was nice to see.

“You should have come over, babe!” she insists. “It was exciting. You can’t be blasé about this stuff, it was Lily on Jools! It was a big deal for us! Everyone’s acting-the-cool so much that it’s actually not cool. One thing my dad told me was that there’s not a certain way of behaving just because you’re an actress — although my publicist would disagree.”

Anyway, in the past year she has increasingly avoided “the paps”, changing her social patterns, keeping her head down a bit more (“people get such an image of you, they think you can’t be anything else”). She wants to be “an amazingly successful actress, of course” but she is not in a mad rush.

She still loves her fashion, and has modelled for Vivienne Westwood and Pam Hogg (“all girls should get to walk down a catwalk once in their lives”). She has had meetings with some lovely people in LA, but isn’t “at that Jennifer Aniston rom-com stage. I still want to take risks and draw on my ‘edginess’, if you want to call it that”. She’s aware that perhaps some casting directors have her typecast as “this zombie-killing, drug-taking absolute nutty bitch”, but is happy to prove otherwise.

“I want to keep growing as an actress and a person. I hate the thought of being 24 and thinking, ‘Oh, I’m grown up now’. I want to keep my naivety and innocence as long as possible.” A pause. “Though I don’t think I’ve got a lot of innocence left,” she sighs, then laughs a laugh that could be hers, or could be Sherbet Gravel’s.

The Fastest Clock in the Universe, Hampstead Theatre, London NW3 (020-7722 9301), until October 17; Philip Ridley performs his poetry after the performances on Oct 9 and 10

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