The heiress's old clothes

Here's the situation: you are 31, newly divorced from the son of one of the world's richest men, and you have returned, three children and a fairly good settlement in tow, to the city you left 12 years before. What do you do? You cannot pick up where you left off as a 19-year-old; your friends have grown up, got degrees, got jobs, got married, moved to Sussex. You . . . well, you cocooned. How do you adjust? You are, effectively, a pseudo-teenager, still in the process of becoming.

Actually, you are Daphne Guinness. And nine years after she came back to London to restart her life following the end of her marriage to Spyros Niarchos, the son of Greek shipping magnate Stavros Niarchos - nine years in which she used an extraordinary eye for couture to establish herself as one her generation's great English eccentrics - Guinness is finally beginning to shed her costumes and emerge from her chrysalis: physically, emotionally and professionally.

Guinness is famously tiny - size 2 or 4 or 6 or 0, depending on the designer - with latterly famous skunk-striped hair, a pointy chin of the sort often described as determined, big blue eyes and a penchant for heavy metal diamond jewellery. In person she is pretty and softer than she often looks in pictures, when her chin and hair can convey a harsher geometry than exists in reality. She has developed an identifiable personal style - white shirt, platform stilettos of the pole-dancer kind (custom-made for her by House of Harlot), skinny black trousers and black New Romantics-type jacket - that, along with her name and connections, gets her lots of play in the society/celeb pages.

Next week she is auctioning a big chunk of her wardrobe - about 1,000 pieces, with pretty much every haute-designer represented, from Chanel to Dolce & Gabbana, Versace, Valentino and Yves Saint Laurent (though it is mostly ready-to-wear) - to raise money for the charity Womankind, which focuses on lifting women out of poverty. At least that's the public reason. The private reason has to do with growing up.

"The clothes represent a not very happy period in my life, and I wanted to say goodbye to it," says Guinness, though she is vague about whether that period relates to her marriage itself or the difficult time after the marriage ended. In any case, though the sale, which is being organised by Kerry Taylor Auctions, may represent some sort of psychological maturation, Guinness still talks with the jumpy subject connections of an adolescent: doubling back on herself, questioning her own statements, rethinking her assumptions almost before she has articulated them.

Indeed, in person it's hard not to feel maternal and protective of her, even though she has raised three children (two boys and a girl, now 18, 16 and 12), talks confidently about the mathematical equations connecting linguistics and music, has a black crocodile Birkin larger than many aeroplane carry-ons, and is in the process of commissioning a diamond gauntlet from jeweller Shaun Leane. Maybe it's the gauntlet. Why would a grown woman need a functioning piece of armour?

"I always wanted a piece of armour," says Guinness, who favours three-knuckle rings from Los Angeles jeweller Lorre Rodkin, a specialist in heavy metal punk and skull-type pieces. "When I was a child there were always suits of armour in our houses, and I wanted to be Joan of Arc."

The youngest daughter of banker and brewery heir Jonathan Guinness, Lord Moyne, and Suzanne Lisney, Daphne was raised in assorted baronial homes in Ireland, Warwickshire and Cadaques; her paternal grandmother was Diana Mitford (later Lady Mosley). She was all set to go to Guildhall and wanted to become an opera singer when she fell in love, got married and pregnant, and switched dreams.

Psychologically, the Leane piece - " Blade Runner meets Boudicca" - feels almost too transparent. A recent British Vogue profile of Guinness speculated that it had to do with a childhood accident with a lawnmower that almost cut Guinness's arm off but, in all likelihood, it's simply a more overt expression of her covert use of clothes as protection and camouflage. Like Andy Warhol, who said he dyed his wig platinum because then everyone noticed the dye but not the actual hairpiece, Guinness has leveraged fashion's ability to distract from whatever else might be going on, transforming her exterior into the subject at hand.

Still, she is surprisingly open about what's going on in her head when asked. One of the biggest misconceptions about her, she says, is that she is unapproachable (the other being that she only cares about clothes and parties), and she certainly makes a considered attempt to answer most questions. This is partly, of course, because she understands the value of publicity and wants to raise as much money as possible for her sale - "If it nets about £50,000, I will be happy" - and she knows the quid pro quo involved. Despite being photographed at many gala events, she says she dislikes public charitable parties, and originally wanted the auction to be private, not so much because she didn't want her personal effects aired in public as because she didn't want the auction to be about her but about, say, the fabulous fuchsia, pink and purple sequinned Dolce trousers being sold, or the classic Chanel bouclé suits. In the end, however, she was convinced the financial promise of going public outweighed her reservations.

"It's the first time I've done anything like this," she says. "I don't even like going to black-tie fundraisers because of the gap between the event and what the event is usually for," she says. "I've always wanted to do a charity dinner where the guests are asked to calculate the cost of their dresses and cars and stuff and then give that money and come in a sheet. It just seems absurd to be sitting there dripping in diamonds and watching this depressing video about everyone dying. I hate people who say things at dinner they won't say publicly . . . Oh boy. Now I'm really on my soapbox. But I'd so much rather pay to go to a lecture about physics or something."

The auction is probably a one-off, though maybe not: "When I came back from a trip the other day, I thought, 'Oh God, just sell it all'." In fact, many of Guinness's projects seem to be less part of a life plan than life experiments. When she returned to London, she says, she wanted a job but was "pretty unemployable. People thought, 'She doesn't need a job,' and I did want to be able to take care of my kids, so my options were pretty limited. It was difficult, because I didn't know how to get into the system."

Guinness attended a course in politics in the University College London mature student programme, took some life-drawing classes, spent three months at the Royal Academy of Dramatic Art, three months at the London Academy of Music and Dramatic Art, and started hanging out with style doyenne Isabella Blow again, whom she had known since she was a teenager (according to Guinness, Blow's grandmother was Guinness's great-grandfather's mistress). It was Blow who introduced her to the Alexander McQueen/Shaun Leane gang, and Guinness threw herself "into this creative milieu. I was more used to those sorts of minds - does that make sense? - because I'd always liked books and music and art." During her years away she had, more because of opportunity than anything else, become a fashion connoisseur, working with designers such as Azzedine Alaia, Karl Lagerfeld, Hubert de Givenchy ("he and his boyfriend were great friends of my grandmother's") and Oscar de la Renta ("I love him and his wife; I know them quite well"). It is the process of creating a garment she especially enjoys.

"It was my hobby," she says, "but because I had no degree and lived a fairly secluded life it became more." Despite her more esoteric interests, she is a client of Starworks, the PR-meets-celebrity wrangling management firm, and contributes a blog to www.starworksny.com, where she describes herself as "a little bit of everything: artist, writer, jewellery designer, film producer". The film she is talking about is Cashback, a romantic comedy about an insomniac aspiring artist, directed by photographer Sean Ellis, whose short of the same name Guinness also produced. The film led her to Adrian Joffe, president of Comme des Garçons, who suggested she design a capsule collection of white shirts for his haute boutique Dover Street Market in London. Now she's on her second collection, and Joffe, who handles all the CdG fragrances, has also made a perfume modelled on a homemade one of Daphne's, to be sold this autumn. Guinness herself says: "I am jack of all trades and master of none . . . I'm an ideas person, so if someone comes to me with an idea, I can work with them to make it possible, brainstorming . . . "

The unkind could call her a dilettante but it's more as if she's trying to find a place that works for her, not unlike the late Isabella Blow, who, like Guinness, was called a muse but functioned more as a fashion world facilitator, introducing and promoting new talent to older money. Guinness is aware of the similarity, and says: "If you're too idealistic about this kind of work and not practical, you can end up broke. I'm more careful about that. You can't support everyone." She is also aware of the criticism that can be levelled at her, and is careful to make no claims for herself; she is not a "tycoon", not a "patron - that sounds too serious"; she works in "the smallest way possible". When Kerry Taylor tells her museums will be interested in her couture collection in the years to come, Guinness's voice goes up a notch and she says, "Really?" "Oh yes," says Taylor. "It is historically important. You are an important woman."

"Really?" squeaks Guinness, as though she finds this extraordinary. Even though she identifies herself partly as a collector, her career search is still "a work in progress" - not unlike her hair, with which she has been experimenting since she was 12 (with a brief hiatus for pregnancy); not unlike herself.

Lately, for example, she has become interested in politics (she placed a bet on Barack Obama becoming US president two years ago with her bookie, but doesn't remember how much), and would like to do more, "even if it's licking stamps". She's written some columns for the Spectator and is interested in writing more, and, maybe, working with a non-governmental organisation, too. When the diamond gauntlet is completed she and Leane plan to use different sections as prototypes for pieces that will be available at Dover Street. This may be done from London or it may not; before Christmas Guinness sold her house of four years in St John's Wood and she is still looking for another place to live. "The funny thing," she says, "is people still say to me, 'Oh, you're back? When are you going again?' and I've been here for years!" Right now she's in a suite in Claridge's along with some of the clothes she is not selling, and she talks longingly of New York. Her oldest son is enrolled at Yale.

So she hopes things go well on the 29th. But, really, she has no idea where she will end up.

Daphne Guinness Fashion Auction, Tuesday April 29, 2 pm, La Galleria, 30 Royal Opera Arcade, London SW1Y 4UY

Previews: Monday April 28, 9.30am-5pm,Tuesday April 29 9.30am-12 noon.

Catalogue: online with images www.kerrytaylorauctions.com

Vanessa Friedman is the FT's fashion editor.