Vivienne Westwood: 'I'd like to be the last person alive ... just to know what happens!'

She found fame in the punk years with partner Malcolm McLaren. Now, she cares more about culture and conservation but still enjoys a good gossip. Sarah Morrison meets Vivienne Westwood

Dame Vivienne Westwood is in the mood to talk. The 71-year-old anti-establishment figurehead turned national treasure has lost her glasses, can't read her book, and is looking to me to entertain her on the 105-minute train ride from Bristol to London. Her eyes, framed by the familiar thinly drawn-on red eyebrows, are focused intently on mine. The godmother of punk is inches from my face, has a tea by her side (a drop of milk, no sugar) and is wearing a T-shirt under her oversized, couture, pin-striped suit, that says, "Get a Life". The pressure is on.

She's not one to recoil from a debate, and her eyes dart back and forth as she discusses art, the Queen's wardrobe, her relationships, conspiracy theories, Bertrand Russell, drones, saving the rainforests, Tracey Emin, and her love of Proust and Pamela Anderson, in equal measure. She pauses only when an announcement booms out – she can't talk with noise in the background – and answers my questions in any order she likes, and at any length, reassuring me, kindly, that "everything is connected".

But before she shows me exactly how, she wants to right some wrongs. A self-proclaimed sceptic of feminism – she tends towards the "heroic personality", irrespective of gender – she is keen to talk about the men in her life. First up: former partner and Sex Pistols manager, the late Malcolm McLaren. They first met in 1965, when he was a 19-year-old student and she was a married mother of one, and soon opened their own shop, called Sex, on the King's Road, sprayed with pornographic graffiti, selling fetish wear, and kitting out the elite of Britain's punk scene.

McLaren fathered her second son, Joe, and when the music mogul died two years ago, of a rare form of asbestos-inflicted cancer, it was she who led his tributes. Always choosing her relationships around "who can stimulate [me] mentally", she admits that when she first met McLaren, she "didn't fancy him at all". But, while she says he was "very charismatic", a "special person" and a "real phenomenon", she shakes her head when I ask if they remained close friends until the end.

"Well, Malcolm's dead so I can tell you the truth about him," she says, leaning in. "He really needed success, he hated the older generation, he needed to score over people and he only dug at things for what somehow he could impress people with. He wasn't interested in ideas, he was just interested in being one-up on people all the time. So I got bored. I have to go digging away." Reducing her voice to a whisper, she continues: "Actually, he was terrible to me, Malcolm; he tried to destroy everything I had; that was his main aim at the point when we split up. He was very bad to Joe as well, really rotten to him. He even saw him as competition in certain things." McLaren explicitly stated that his only son should not be included in his will and left his estate to his girlfriend, Young Kim. Despite the legal battle that followed, it was revealed earlier this year that Kim was the sole heir.

Candid but not unfair, Westwood decides to stop there, adding only that while he was "very messed up", he was "quite a happy person at the end". She is equally frank about her friend Tracey Emin – "she has something every now and again, but sometimes [her work] makes you cringe, it's so ... indulgent" – and the Prime Minister – "I'm not impressed by David Cameron". But she lavishes unfettered praise on those she respects. Mr Cameron's former political adviser Steve Hilton, who asked to meet her to discuss her activism, is described as "absolutely brilliant", while her "dear friend" Pamela Anderson, her latest environmental mentee, is "fantastic". She explains: "She just wants to learn so much. The last time she came over, she wrote me a text saying she had thought about our discussion so much she was awake until three at night."

And it's the pursuit of intellectual cut and thrust that now chiefly occupies Britain's most coveted fashion designer. She tells me that these days she rarely agrees to do profiles on fashion, and uses her platform only to discuss the two campaigns closest to her heart: the environment and the fact that society is "dangerously short on culture". Fresh from a sold-out speaking engagement at Bristol's Big Green Week – a nine-day symposium positioning itself as the Edinburgh Festival of sustainable ideas – Dame Vivienne is keen to talk about both.

After reading the environmentalist James Lovelock, proponent of the Gaia hypothesis, about five years ago, she came to the conclusion that human beings are "an endangered species". Since then, she has written her own manifesto, "Active Resistance to Propaganda", which uses characters as diverse as Aristotle, Pinocchio and a pirate to discuss ideas of excessive consumption, and donated a reported £1m to the charity Cool Earth, which works to protect endangered rainforests. She even proposes making models the new face of the environmental movement.

Known for her mantra "buy less, choose well", the former anti-royal suggests it would be "really great if the Queen could wear the same outfit every time she did a public occasion – it would make the point that you don't always have to change your dress to be important in this world". And while one could accuse a businesswoman whose fortune was made in high-end fashion of some hypocrisy on this, it is clear she is nothing if not an idealist. She is sporting a badge emblazoned with her manifesto's initials, "AR", and one of her "most treasured items of clothing", her scarf, reads "Save the Rainforests". When the man with the snack-trolley hands her a tea topped off with a plastic lid, she quickly returns the offending item, making him promise not to discard it and assuring him "it's not contaminated", seemingly unperturbed when he mocks, "Oh yeah, all that 'Save the Planet' stuff."

In fact, when Westwood, who says the proudest moment of her life was becoming a trustee for the human rights organisation Liberty, is not hoping for a "way of using money that's more meaningful and more targeted towards human interest", she is cycling around London in her "Tree T-shirt" – a top she breaks off to ask her husband and creative partner, Andreas Kronthaler, to bring along for her to wear at her next engagement, an evening at Prince Charles's reception for Men's Fashion Week, followed by a concert at the Royal Festival Hall, London. Perhaps one of the few interviewees who wants to carry on talking long after our allocated time, she interrupts our conversation only to take calls from Kronthaler, who she describes as "one of the most intelligent people I have ever met".

"It's incredible. He's creative, actually – it's his imagination, what he sees, he's so visual, so aural, not literal, like I am; he just gets this direct knowledge from places and tells you things you cannot believe," she says of her partner of more than 20 years. She insists he is responsible "for as much of our design as I am. In fact, most of the time, I feel like his assistant when we work together. I have to listen to him or he'd really get upset." If it seems strange that such a meticulous designer would share the burden of her work so easily, it is because, for her, fashion is now, well, a little boring.

"I have always had something called 'all these other things'," she tells me. "I think, when I finish this pair of trousers, I can do all those other things I'm really interested in, like reading this book, or trying to raise public awareness about the environment. I would really like to get involved in theatre – not just visual, but also content, but I don't think I'd have time," she concludes, before admitting that she thinks she will carry on designing "until the end".

The time she does have, she seems determined not to waste. Westwood is no fan of television, movies or newspapers, and refuses to get her own mobile phone. Her newest resolution is to spend one day a week reading only fiction. When I ask her how she relaxes, she admits, "I am in my own head most of the time." But of one thing she is sure. "I think I've got wiser," she says. "At one time, I was very angry. I even treated fashion like a kind of crusade: you were either with us or against us, that kind of feeling. Now I know we need ideas, not kicking down a door."

And while she seems disillusioned with the 21st century – a time that is so devoid, in her opinion, of meaningful culture – she ends our discussion optimistically. As the train pulls up to the platform, she turns to me , eyes alight: "I'd like to be the last person alive in the world!" she says. "Yes, I'd like to know what happens."

Curriculum Vitae

1941: Born Vivienne Isabel Swire to Gordon, a cobbler, and Dora Swire, a cotton-weaver, in Tintwistle, Derbyshire.

1958: Family moves to Harrow, north London. She studies at Harrow art school for a term before training as a school teacher.

1962: Marries Derek Westwood, a Hoover factory worker.

1963: Gives birth to her first son, Benjamin Westwood, now an erotic photographer.

1965: Meets Malcolm McLaren, and separates from Westwood.

1967: Has a child with McLaren, Joseph Corre, founder of Agent Provocateur.

1971: Opens "Let It Rock" boutique in Chelsea, changing its name to "Sex" in 1974.

1976: Begins dressing Sex Pistols, the band managed by McLaren.

1980: "Sex" becomes "World's End" which still sells the Vivienne Westwood collection.

1981: Shows her first collection, Pirates, at London Fashion Week.

1989: Poses on the cover of Tatler dressed as Margaret Thatcher.

1990: Named British Fashion Designer of the Year – an accolade she wins three times.

1992: Receives an OBE and marries Andreas Kronthaler, 25 years her junior and one of her design students.

1998: Awarded the Queen's Award for Export.

2004: The Victoria and Albert Museum shows a major retrospective of her work.

2005: Works with civil rights group Liberty, designing a T-shirt to promote habeas corpus.

2006: Made a dame "for services to fashion".

Rachel Speed