Halfway through the photo shoot, Vivienne Westwood disappears into her office and reappears in a clinging semi see-through sequined dress in graduated autumnal shades with a pair of five-inch red patent leather platform heels on her feet. Over the dress, is a... well, what exactly? Who can say, but if I was forced to describe it, I would perhaps call it a pseudo-apron - a piece of black silk that hooks over the shoulders and around the waist and that looks like the sort of thing that Darth Vader might wear if he was about to do a spot of baking.
'Hmmm,' she says, frowning into the mirror. 'There's something not quite...' and she goes to take off the corset from under the dress and then puts it back on over the top of it. 'Shall I wear my horns?' she asks, rhetorically as it turns out, and puts on what at first looks like a tiara but is in fact a silver headband with two delicate silver nubs on it; the kind of thing that young stags butt up against each other with, or that a member of a particularly upmarket hen party might wear. They sprout from her forehead beneath carefully arranged tangerine curls.
She peers into the mirror again. It's a wonderful spectator sport, watching Vivienne Westwood get dressed, Dame Vivienne Westwood - for she was invested last year at the Palace and wore her horns and an 'urban guerrilla's cap' but managed to restrain herself from twirling knickerless in front of the paparazzi as she did when she got her OBE. It's the element of suspense I like best: I've absolutely no idea what she might put on next. Her past hits include chicken-bone T-shirts (cleaned, drilled and stitched on to spell out the word 'fuck'), granny pants decorated with male genitalia, flesh-coloured tights worn as trousers and adorned with a modesty fig leaf, towering platform shoes that sent Naomi Campbell tumbling, crinolines, bustles.... I watch her adjust her horns. What next? A prosthetic hunch? A club foot?
'I'm just not sure it goes ....' she says and I wonder which bit of the outfit she's referring to: the Darth Vader apron, the corset, the see-through dress, the silver satyr's horns .... 'It's the earrings,' she says finally. The earrings? They're a pair of totally inoffensive plain gold hoops. Although of course, that's probably the point. Everything about Vivienne Westwood has a touch of the extraordinary to it, whereas the earrings are simply earrings, an overlooked sort of concept in Westwoodworld.
The clothes aren't shocking, of course, or at least I'm only very mildly taken aback when I realise that the get-up isn't simply for the benefit of the camera and that she's actually intending to wear it. Outside. On the street. To a charity theatre gala. It's her demeanour that's so much more surprising. I've been reading her manifesto and her essays and collected thoughts on her website, www.activeresistance.co.uk, and, in print, she comes across like the most awful know-it-all; a cultural snob of the worst kind, lecturing and chastising and ordering you to sit up properly and learn about culture and to go and look at 17th-century Dutch art and not to bother with any of that modern rubbish.
On the page, she's the Alan Sugar of art: bossy, over-demanding, largely humourless, and having seen the photographs of her in her chicken-bone T-shirt days when she and Malcolm McLaren invented punk from their shop on the King's Road, I'm expecting something at least a little bit scary. In the flesh, though, she's nothing of the kind: she has a rather soft and consoling manner and a lovely northern accent of the un-poshed-up variety that you simply don't get to hear all that much of in public life, with the possible exception, perhaps, of Janice Battersby.
But I'm here for the express purpose of being lectured and it's Westwood who manages to ask the first question. 'Have you read my manifesto?' she asks, fixing me in the eye. 'Oh yes,' I say, and could add 'several times' although never quite in one sitting owing to what the Guardian, at its first public reading performed at the Hay Festival, noted was its 'somewhat hard-to-follow' nature. ('One man rose, theatrically, sighed loudly and left the tent,' the report went on, cattily. 'Many others followed suit.')
The manifesto is called Active Resistance to Propaganda and is full of ideas about Art and Culture and is narrated by more than 20 characters including Alice in Wonderland and Pinocchio. To give you some indication of the scale of Westwood's ambition, the introduction reads: 'I make the great claim for my manifesto, that it penetrates to the root of the human predicament and offers the underlying solution.'
Westwood merely blinks when I say, that is quite a big claim, isn't it?
'It is. I think it's really serious. It's the result of a lifetime's thinking in the fields of heretical opinion. There is so much that people take for granted. And words even have come to mean their opposite, you know like "imagination". Things like this. People don't know what "culture" means. I thought it was very important to define culture.'
There's about a million holes you could pick with her argument, not least of which is that the only 20th-century writers worth the candle are Bertrand Russell and Aldous Huxley and that all modern art is rubbish (up to and definitely including that produced by her good friend and sometime Westwood model, Tracey Emin: 'I've always been honest with her. I said to her, why are you so satisfied with it? That is me being friendly towards her. I have to be honest, I can't help it.')
Some might say that claiming to have found the answer to everything is also perhaps somewhat problematic.
'It's a philosophy of life,' she says. 'A practice. If you do this, something will change, what will change is that you will change, your life will change, and if you can change you, you can perhaps change the world.'
Her aim is to deliver her manifesto Al Gore-style, maybe once a month, to whoever's interested. All she wants is to 'sow the seeds' of change.
Put her on the Late Review and she'd be mauled to death by Germaine Greer and Michael Gove. She comes over as some latterday FR Leavis as played by Julie Walters, holds fast to the ideas of classical civilisation and high culture, likes tradition, hates change, not to mention all TV, cinema and the internet, and I can't help thinking that her argument might have been more powerful had it been expressed as an argument rather than as a fantasy vignette, but I find it strangely restful gazing on her horns and listening to her talk about nationalistic idolatry and the like.
And it's a great achievement, surely, to reach the age of 66 and still want to change the world; there's an unshakeable air of innocence about her that has somehow survived a whole lifetime of the air-kiss-you-as-soon-as-stab-you-in-the-back vipers of the fashion world. What's more, the usual explanation for her behaviour is simply inadequate: it's neatly summarised by the Telegraph's description of her last month as 'the beloved bonkers old lady of fashion'. Part of it perhaps is that she designs frocks for women with things like breasts and hips - every extant photo there is of Nigella Lawson in a cocktail dress is by Vivienne Westwood - which is generally considered another aspect of lunacy since every other fashion designer knows that such things spoil the line of the clothes. But beyond that, she's a woman of a certain age, a grandmother, from the north of England, and even if she didn't gallivant around dressed as a woodland faun, she'd still be horribly patronised; a slight improvement possibly on any other century in which she would probably have been ducked in the nearest river.
She's unorthodox, strangely and impressively unworldly, but not mad, or even that Great-British cuteism, bonkers. By her own account, 'intelligence is composed mostly of imagination, insight, things that have nothing to do with reason', and what Westwood has in spades is imagination. She's endlessly creative. Which is just as well as she's on altogether less solid ground when it comes to the reason part of the equation.
Her manifesto begs certain questions to be asked. Such as, isn't it just a bit contradictory to design clothes and to tell people to stop shopping? Or as Suzy Menkes, long-time fashion editor of the International Herald Tribune, put it after one of her last collections: 'How dare she send out a show laced with anarchist messages, take her bow in a clinging dress with the word "propaganda" spiralling around her ample figure, announce that the spirit of her show is "the more you consume, the less you think" and then take the opportunity to launch her collection of punk safety pins in diamonds?'
'Mmm. Mmm. Anyway,' says Westwood. 'I don't feel very comfortable defending my fashion except to say that people don't have to buy it. You do have to consume. You have to live. If you've got the money to be able to afford it, then it's really good to buy something from me, but don't buy too much. I think stamped-out clothing is just for clones and I think that everybody looks terribly miserable. Fashion is life-enhancing and I think it's a lovely, generous thing to do for other people.'
Read a potted account of Vivienne Westwood's background and you could mistake her for a Barbara Taylor Bradford heroine - plucky, northern, of humble birth, who hauls herself up by her own bootstraps. Her father worked in the Wall's sausage factory, her mother was a greengrocer's assistant, and she grew up in the Pennine village of Tintwistle until her parents moved south to Harrow to run a post office. She did a term at art college before turning to teacher training and was Vivienne Swire until she met Derek Westwood, her first husband, a factory apprentice, and had the first of her two sons, Ben.
So far, so un-Taylor Bradford. And then Malcolm McLaren arrives on the scene, former art student, future manager of the Sex Pistols, relentless self-publicist, a 1970s version of the dashing but potentially caddish lord of the manor if ever there was one. And, as romantic heroines do, Westwood fell pregnant, with her second son, Joe, on more or less their first night together.
'We were both so stupid about sex. He thought I was using something and I thought he was and that was that really.' They stayed together for 12 years, a great creative partnership that gave the world the visual grammar that became punk. McLaren took out a lease on a shop on London's King's Road and Westwood began designing clothes to fill it.
Meeting McLaren was one of the defining points of Westwood's life, although they no longer talk. 'I mean I'd certainly say hello if I saw him but no, sadly, we're not friends any more.'
I'd read that he used to send you patronising letters saying how proud he was of you, I say.
'I don't really want to discuss Malcolm and the way that I think he looks at me. Because I would end up saying bad things about him and I don't want to do that.'
It hasn't all been plain sailing. She gave Adam Ant his pirate look, and then came the Buffalo Girl look but, by the end of the Eighties, she was the designer's designer, feted by the likes of John Galliano and Issey Miyake, but considered too extreme, too uncommercial. Her mini-crinis were laughed off the catwalk only to be nicked by every other designer in the book and reappear two years later to critical acclaim. Now, though, her reputation is unimpeachable and her turnover impressive. She's won British Designer of the Year three times, and four years ago, the V&A mounted a retrospective of her work that's been touring ever since.
The business is now run by an Italian, her ex-lover Carlo D'Amario ('we get on so well and he's such a good manager'), and working alongside Westwood is her third husband, Andreas Kronthaler. He's 25 years her junior and they met when she was teaching in Vienna and he was her student.
In interviews, she always makes out that they're the very picture of domestic contentment, which always raises your suspicions, but she's generous to a fault when talking about him. They have been together 15 years now and, in a single stray cutting from Time Out, I find that he is referred to as 'bisexual'. Is he, I ask?
'Well, yes, I think he probably was. He doesn't mind if people say that, he doesn't care at all. In fact he thinks it's quite good that nobody really knows. And I don't really know.'
'You've never asked him?'
'No! No, I haven't. I just know that he's deeply interested in me and I don't have any worries about Andreas. I'm hedging a bit. I probably know a bit more. I would guess yes, but I don't really know. But anyway. Hmm.'
Westwood and McLaren's shop was at one point called 'Sex'; her oldest son, Ben, is a porn photographer; and her second son, Joe, is co-founder of Agent Provocateur, but her own take on the subject is that 'I love that Jean Shrimpton quote. She did this interview where she was asked what was it like with her and David [Bailey] and she just said, "Sex has never been high on my list of priorities", and I thought that was just brilliant. And that's the same with me.'
Andreas goes on holiday somewhere sunny with his friends, while Westwood stays at home and catches up on her reading. They're not the most obvious of couples, so much so that, 'when we first got married, I didn't tell anybody. In fact, what happened is that we had a relationship and at the time Austria wasn't in the EU and it was very difficult to get a work permit, so I told him you'll have to marry somebody. And he said, "I have to marry you!" I just thought, "What?" I felt too old to be married to somebody that age so we didn't tell anybody for quite a long time.
'Not anybody, in fact. My mother only found out when she read about it in the paper. I think I'd been married to him for about three years by then.'
But she knew you were in a relationship with him?
'No, I don't think she did, really.'
I don't get to meet Andreas, disappointingly. I'd read in a previous interview that he likes to match his underpants with his outfits and I can't help thinking of Bruno, Sacha Baron Cohen's gay Austrian fashion-designer character, an impression that isn't totally eradicated by a photo of I see of him in which he's dressed in a tight blue suit with a big bushy beard and looks rather like a 1970s catalogue model. I lap up tales of their relationship though; every snippet is a gem. Westwood tells me that it was Andreas's idea to move to a bigger place 'because where he comes from in Austria, the apartments are really big. And my flat was really quite small even though I'd lived there with Malcolm and two children. So we took out a mortgage on this wonderful house. And Andreas, over the period of a year, went to his favourite shop, Peter Jones, got fittings, just slowly did things, put certain carpets and furniture in. I went and visited it once, no twice, once to do a shoot with David Bailey and once Andreas asked me to go there and help him choose some paint.
'And then one day, he said to me, "Would you like to move into the house? We could move today, it's ready." He said, "It'll only take us about three hours to pack because I didn't have very much stuff". And I said, "Oh let's go tomorrow. And off we went". '
I can't believe that anyone can pack up a lifetime's worth of possessions in a couple of hours but apparently Westwood did. It turns out that she's had more practice in the art of non-consumerism than you might imagine. When I ask her what she spends her money on the only things she can think of is 'books'. Isn't there anything else? 'I'm not very acquisitive. I don't have any art objects or anything like that. Hmm. Well, I've got someone who comes in twice a week to clean. Apart from that, well, I don't know. Anyway.'
She doesn't buy clothes or knick-knacks, or go on expensive holidays. She loves art, her Dutch masters, but doesn't feel the need to hang it on her wall. And it's this that, in the end, does, I think, give her a certain moral authority. Can I really say that? She flogs overpriced diamond brooches, after all, and talks about producing her own version of Mao's Little Red Book: 'The manifesto will be the nucleus of it and I will add certain essays as I get the time to do them.'
Hmm. Anyway. As she would say. The funny thing is her insistence on art as timeless and universal when her fashion is the antithesis of the timeless in every way: the ephemeral, always changing, highly specific. Her brilliance lies is creating a moment in time. She's given us the visual backdrop to at least one British decade, possibly two, and yet she endlessly frustrates journalists by wanting to talk about Rousseau rather than clothes.
And it's true, you've got to have an unhurried stretch of time on your hands, and a certain amount of tolerance to get through the Pinocchio stuff. But even though by the end of the interview I've grown strangely attached to the horns ('pagan fertility symbols', according to Westwood), I also notice that every single person I see in her studios is wearing inventive trousers of some description: trousers that sag at the bum, or fold strangely around the crotch, or flare out at the thigh. It's all well and good, of course, but, personally, I don't find it really so mad to think that there might be more, in the end, to life than this. Oh yes, and the Darth Vader pseudo-apron? It's actually 'a silhouette of an animal skin from a prehistoric cave painting'.
· Active Resistance to Propaganda, www.activeresistance.co.uk, was launched on December 1 at the Wallace Collection (www.wallacecollection.org).