Charlotte Rampling has only one scene in her latest film, Life During Wartime, showing at The Times BFI London Film Festival. But, boy, what a scene. In Todd Solondz’s quasi-sequel to his 1998 indie hit Happiness she orchestrates a brutal car crash of a seduction between her character, the intimidating, viciously forthright Jacqueline, and Ciarán Hinds’s Bill, a convicted paedophile just released from prison. Her bitterness and self-loathing fill the hotel room like a heady perfume. “I am a monster!” she snarls, daring her hapless conquest to disagree. It’s unsettling, darkly comic and the stand-out moment in the whole film.

The head-on onslaught against cinematic taboos is a Solondz trademark, but the chilling savagery of the performance is pure Rampling. Coming after her paranoid crime writer in François Ozon’s Swimming Pool and a scene-stealing turn as a suicidal wife in Dominik Moll’s Lemming, there has been rather a lot of emotional violence in Rampling’s career of late.

“Yes, you’re right,” she says. “Directors see you in a certain way so you are invited to play those types of people. You can say: ‘No, I want to change’, but it always comes back. There is something, I think, that inhabits each actor. It comes out. Even if you are playing a lady there is something that people fear.”

So under the very chic dark trouser suit and the understated elegance there is a savage? Rampling smiles her sphinx’s smile. “That’s all a wonderful façade I put on. Then I go and bash up my dog when I get home and kick a few children if I can.”

In person, when I meet her during the Venice Film Festival, Rampling is full of contradictions. She is both formidable and, with her tiny frame, curiously vulnerable. She appears poised but, as the heat of the afternoon sun builds, she’s increasingly distracted and rather agitated. That smooth, low voice that purrs like the engine of a Bentley is punctuated by jagged honks of awkward laughter. There’s a tension in her that rarely abates.

So is acting cathartic? A pressure release? “I guess so. Anger, rage and all of the more violent things that we have racing around inside us — that’s what we use. Rather than using it more in everyday life, we can channel it through a creative force. That’s why creativity is useful to people even if they don’t do it as a profession. Anything. Painting might seem quite tame, but not at all. You can really get things out.” She blurts out a hollow laugh.

Rampling has had to deal with more than most over the years. Born in Sturmer, Essex, to a painter mother and an Army officer father, she emerged from an exclusive education in France and England and plunged headlong into the Swinging Sixties. Her partner in crime was her older sister Sarah. But when Rampling was just 21 and had barely started out in her acting career, Sarah, 23, committed suicide after she gave birth prematurely.

The grief was bottled up and filed away. Rampling and her father agreed that they couldn’t tell her mother the truth about what had happened. It was not until her mother died in 2001 that Rampling felt able to talk about the tragedy. She named her character in Swimming Pool Sarah.

But until then Rampling struggled with persistent depression that culminated in the break-up of her marriage to the French musician Jean-Michel Jarre. “I used to have a lot of therapy but not any more. I have a marvellous acupuncture guy and we talk a lot. It’s all part of what I suppose you could call a holistic approach.”

Understandably, Rampling put her acting career on something of a back burner while she struggled with her demons. But in the past decade she has exploded back onto the scene as the muse of Ozon and a new generation of young directors. She seems to be more in demand than ever, with roles in everything from the high-profile Kazuo Ishiguro adaptation Never Let Me Go to the British 3-D dance flick StreetDance. Does she still love the job? “I love it and hate it, I always have. But I love and hate everything. I’m very volatile. And that is perhaps where that wildness in my work comes in. Controlled wildness.”

Specifically, she says, she hates a lot of the actual filming process. “I’m just like that — that’s how I function. It’s almost like a manically depressive type. If you keep it under control it’s OK. But I think a lot of creative people are like that. You push yourself into ... states.”

The way she describes it it doesn’t sound like fun at all. “Well, no, it’s not,” she says, her voice dropping to a mutter. “But I don’t talk about that. It’s not a thing to talk about in interviews anyway. You have to make people think it’s all wonderful.”

However ambivalent she is about the job, the fact remains that at an age when many actresses are becoming invisible or settling into granny roles, Rampling, who is 63, is still playing mercurial, sexual, difficult women with an intensity that has not diminished since her breakout performance in The Night Porter in 1974. “I demand things of myself. You can’t ask people for roles, although some actresses do. But if you don’t do that, you have to wait until somebody gets the idea of you. So you sort of put feelers out. It’s all to do with witchcraft and magic.”

It also helps that Rampling naturally looks great, seemingly without the help of the surgeon’s knife. “Have I? Or haven’t I?” she says playfully. “I wouldn’t say! Nobody knows. But no, I’m lucky because I haven’t really needed it. People think they need it and there’s not much you can do to stop them having it.”

Actresses, she says, feel pressured to take the plastic surgery route, particularly in America, but they can find that it limits the sort of roles they can take. “That’s what the producers and directors in Hollywood say. There’s no one who shows their proper age. And that’s what I’m having fun with. I can make myself look quite horrendous onscreen, but it doesn’t really matter to me. All my expressions are my own. ”

Life During Wartime, at the LFF: Vue 6, tonight at 4pm, and Mon at 6.15pm

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