She used to get mad ... now she's getting even

The fashion world fell out of love with Katharine Hamnett when she started putting 'green' before greed. These days they can't get enough of her

It looks like the Eighties. Suddenly there are all these plain white T-shirts bearing bossy logos like 'Save the Future' or 'Choose Love' (tough choice) in big black lettering and you think, 'Where have I seen those T-shirts before?'

And, if you are as old as me, you remember Katharine Hamnett in 1984, frisking into Number 10 to meet Mrs Thatcher, wearing a T-shirt saying '58% don't want Pershing' (missiles), which was one of the great fashion comedy moments of the decade. But presumably if you are Lily Cole or Peaches Geldof, who weren't born back then, you think, 'Wow, what a wacky new idea!' And so you wear these T-shirts all over the place and suddenly Katharine Hamnett is hot, hot, hot again, which is pretty strange for someone who seemingly disappeared almost 20 years ago.

But the real reason Hamnett is hot is not because of some gruesome Eighties nostalgia but because fashion has finally caught up with her. All those wilderness years when she was out of sight, she was working on the problem of how to make fashion more ethical, more environmentally sound, how to produce clothes that didn't use petrochemicals or pesticides, that relied entirely on organic and recyclable materials. The fruits can now be seen in Tesco - a range of Katharine Hamnett clothing in organic cotton that is guaranteed not to harm the planet. Or indeed the purse, because it is commendably cheap.

So anyway, Katharine Hamnett is back and I met her in her great white hangar of a studio in Highbury, North London, before galloping down the road to have tea and about a million cigarettes in her favourite Turkish café. She looks rather French, with her long straight dark hair, long thin face and long thin body, and certainly doesn't look like someone who turns 60 this year. She is enviably svelte in a black V-neck Smedley sweater and black straight skirt - one of her two 'uniforms', she says, the other being jeans - except that she is wearing Ugg boots, which she needs, she says, because she is going on a Greenpeace demonstration tonight and might have to swim. Sorry? What? 'On a boat,' she exclaims impatiently. But isn't it rather difficult to swim in sheepskin boots? 'Well, of course, I'll kick them off!' She talks in a breathless rush, like the Cheltenham Ladies' College schoolgirl she once was. I wish I had known her then: we could have had fun smoking behind the bike sheds.

But, gosh, her conversation is bewildering. She hops, skips and jumps from Uzbekistan to Mali, from nuclear reactors to foot and mouth disease, from the desertification of China to the increase in childhood allergies that she believes to be due to GM cotton. She certainly doesn't talk like a fashionista. When I ask who she would most like to dress she says Noam Chomsky. When I ask what she last bought herself as a treat, she answers a chipper, to convert wood to compost, for her Majorcan farm. For her next treat she will buy an inflatable canoe and try to surf the Severn Bore. She reminds me a lot of Anita Roddick but she won't thank me for saying that. When I ask if Roddick was her inspiration she says indignantly, 'No, I was before her. And she nicked all our T-shirt graphics, which was a bit of a bugger! Injustice is my inspiration.'

Sometimes, listening to her, I wondered if we've been wrong all these years to believe that Lynne Franks was the inspiration for Ab Fab - much of KH is pure Edina. Take, for instance, her Anti-Anthrax Salad Dressing. 'The height of my anxiety was when I thought we were all going to be anthraxed in 2001 and I just thought, "ohmigod!". I was absolutely petrified and read up on anthrax and apparently not everybody gets it - if your immune system is in amazing condition you don't get it. So I invented this anti-anthrax salad dressing. You take 15 cloves of garlic, which you cut up really, really fine and put in balsamic vinegar for about five minutes, then add the quantity of oil you would normally use. And the vinegar takes the bite out of the garlic, so it means you can eat an unbelievable amount. You'd feel kicked in the stomach if you ate it raw but it's absolutely delicious, everybody loves it. And so far everybody's health has been better, we have far less colds - and certainly far less anthrax!' It seems a bit plodding to point out that actually I haven't caught anthrax either despite my lack of salad dressing - with Hamnett you just have to go with the flow.

I have been waiting to meet her for over 20 years, to apologise. All the time she is raving on, this apology is welling inside me until eventually it pops out: 'Katharine, I have to confess: I'm the one who said you were married to a Rastafarian.' Now it's her turn to look at me as if I'm completely mad, so then I explain. Back in the early Eighties, when I was a newcomer to Fleet Street, the Sunday Express sent me to write a silly piece called 'A Week in Fashion', in which I had to learn everything I could about fashion in a week. Naturally, I didn't learn much but I did notice some recurring themes, one of which was the presence of Rastafarians in almost every fashion show I attended. So I wrote blithely that Rastafarians were the hot new accessory, that every designer seemed to have one, and that Katharine Hamnett had gone so far as to marry hers. Why I ever said this remains a mystery - someone must have told me, but I hadn't made the slightest effort to check. On Monday, Hamnett's office rang the Sunday Express to say that Hamnett was not married to a Rastafarian and never had been, and we had better print a correction. The editor summoned me to a meeting with Express lawyers who informed me with grave faces that this was a serious libel that would cost the Sunday Express dear. They awaited Hamnett's writ and were resigned to paying almost whatever she demanded by way of damages. They waited, I waited, I didn't sleep for weeks, but the writ never came.

'How funny!' she laughs when I tell her. But why didn't she sue? Because, she says, she didn't even know about it: she never reads her own press and her office didn't tell her. But anyway she would never have dreamed of suing, 'Because it would raise the issue - is it a bad thing to be married to a Rastafarian? I think it would be rather a gorgeous thing. In fact, where is he, can you find him for me, this Rastafarian I was supposed to marry?'

This is one of the great things about Katharine Hamnett: she has always put her principles before money. A couple of years ago it brought her close to bankruptcy and she had to sell her lovely big house in Highbury Fields and downshift to Hackney. But that was fine, she said, especially as she was on steroids at the time (for an insect bite) which made her slightly manic and euphoric. And the money from the house enabled her to keep going with her 'project' which finally came to fruition last year when Tesco agreed to manufacture her organic clothing line. It was the culmination of a 17-year obsession.

When she started in the Eighties, she says, she was untroubled by the ethics of fashion and even used to design fur coats. 'And I introduced a lot of processes which are completely harmful - stonewashing, for instance, which cuts down mountains of pumice, and stretch denim, which uses Lycra, a petrochemical derivative. So I am guilty, deeply guilty, in many areas and that's why I'm trying to make amends now.'

Her 'epiphany' came in 1989 when she did some research into the impact of the clothing and textile industry on the environment - 'Because I'm interested in Buddhism and I thought, "Well I'll just check", I don't think there's anything wrong with just making silly clothes but then, nightmare scenario, we found that 10,000 people a year were dying from pesticide poisoning in cotton agriculture! So I spent the Nineties trying to change the industry from within - and that's when things went a bit quiet.'

She tried to interest her fellow designers in using organic cotton, but they ran a mile - she remembers a meeting with Christian Lacroix where he seemed impressed by her ideas, but the next time she bumped into him he couldn't get away fast enough. And she had a row with the British Fashion Council because they wanted her to put on a show 'in some disgusting car park' so then she switched her shows to Paris. 'So I found myself in this nightmare. I slogged on right through the Nineties - designing collections, selling in Japan, manufacturing under licence in Italy, and virtually everything that could go wrong went wrong.' She fell out with her Italian manufacturer when she found he'd switched the fabrics in one of her collections at the last minute and he told her, 'If you keep on about all this ethical shit, you can take your collection and fuck off.' So that's what she did. She decided to tear up her contracts and go it alone - make a range of ethical clothing entirely at her own expense and then try to sell it to a retail chain.

But it was an incredibly hard slog. She would traipse round fabric fairs asking for organic cotton and manufacturers would tell her they didn't make it because there was no demand, whereas now, she says gleefully, she asks if they have organic cotton for Tesco and they all leap to attention and start offering her champagne. Tesco has already ordered 350 tonnes of organic cotton from a mill in India 'so that's great - that's 350 farmers immediately better off'.

Tesco was not her first choice of retailer and 'when I went to see them I thought I was going into the jaws of Hell, but they said they were interested in doing ethical clothing so - good. I don't care if people do the right thing even if it's for the wrong reasons, but actually I think they're really trying.' (Maybe they say the same about her.)

Back at her studio, she shows me a rail of clothes she has designed for Tesco and what is mainly startling, to my eyes, is that they look completely normal. They don't scream fashion statement, nor do they have the Ryvita texture and sludgy colours I associate with eco-fashion. But is it polite to say so? While I am still pondering this dilemma, she points to the buttons on a men's cotton suit and says they are made from palm nuts. 'But they look just like ordinary buttons!' I exclaim. 'That's the whole point. God! You don't want to look eco! You just want to look ordinary.' She shows me the fly zip and says it is guaranteed recycled and recyclable steel, and the waistband is made with all natural stiffening, no glue. 'The hardest thing to do is to get to the point where you can produce clothes that look normal and it has taken for ever, and cost a fortune. We had to stump up for all the minimum quantities, which meant ordering 120 metres of zip tapes to get two zips because otherwise nobody would make it. But we're there now.'

The icing on the cake for her is that she has finally found her Holy Grail: a recycled and recyclable clothes hanger. 'I'd been looking everywhere and I finally found this one little factory in India that was making recycled clothes hangers and I was so excited I practically rang the Tesco technical guy at 3 o'clock in the morning. It's the last piece in the jigsaw. Because I'm very purist about it, and if you're doing ethical and environmental, it's a tragedy if everything is perfect apart from the bloody clothes hanger.'

But isn't there something intrinsically oxymoronic about the idea of ethical fashion? Surely the whole point of fashion is that it is wasteful? We buy clothes we don't need and then throw them away because fashion persuades us they are passé. 'Well we need clothing - we can't go around naked.' But in truth Hamnett is not a great defender of the fashion industry and says she has no friends within it. 'It's full of personality disorders, airheads, dickheads. I worked in Italy for about 30 years and never met anybody who'd read a book. And the fur thing - that was disgusting. People like Naomi Campbell saying they'd never wear fur and they get offered £2,000 to walk down the catwalk and it all goes out of the window.'

So given her disdain for the fashion world, does she ever think she went into the wrong profession? 'Oh yes, totally. I mean I've enjoyed it and it's been very kind to me and I've got two sons and we've had a great time and travelled the world and taken five holidays a year - because I took all the school holidays off and all the half-terms. I was away more than I would want to have been, but when we were together we had a jolly good, consistently fabulous time. But yes, I would have liked to have been a film director, or an archaeologist.' But that sort of thing, rather than a politician? 'Yes, I think the whole political system is useless. If you go into politics you've probably got to wait 20 years to get your squeak in and I can get my squeak in whenever I feel like it. You have far more influence as a maverick than stuck in there with a three-line whip.' And she is indeed a maverick - after apparently supporting Labour for many years she joined the Tories in 1998 but then denounced them as 'tragic ... quite a sexist little bunch'.

So how did she come to make her career in fashion? She says clothes, or at any rate looks, were important in her family. They were all very tall, her mother wore fabulous hats, her father (who was a group captain in the RAF and then defence attaché at various embassies) 'always used to look magnificent in his made-to-measure military uniform with all the scrambled egg [gold braid] - he was 6ft,3in and slim. The whole family was very competitive, and we lived in France and were brought up with French Elle, all that kind of thing. We had all those embassy receptions, and I was put on the diplomatic list on my 16th birthday, so I'd be covered in mud canoeing one second and going to a cocktail party the next.' And she had to make her own clothes because she was too tall (almost six foot) to buy prêt à porter.

The family lived in France, Romania and Sweden while Katharine was growing up, but she was sent back to English boarding school - Cheltenham Ladies' College - and then studied fashion at St Martins. She supported herself by doing freelance design work and already had a good freelance career by the time she left college. (She also made money by 'totting' - buying and selling antiques - and had a good eye. She once found a Lalique cire perdu mirror in a Hertford antique shop, bought it for £6 and sold it at Christie's for £1,300 - the equivalent of three years' student grant.) Then she set up a fashion house called Tuttabankem with a friend, Anne Buck, which did well for a few years, and in 1979 started her own Katharine Hamnett line.

She married Richard Hamnett, a graphic designer, when she was just 21, but divorced four years later - she feared at the time that she would be the first woman in Britain to pay alimony because she was earning more than him, but in the end, she gave him the house and kept the name. Her two sons, William, 25, and Sam, 30, are by a later relationship with the painter Jeffrey Pine, but she has never remarried - 'I say I'm between marriages but it's a lie - I won't get married again. Independent women are better off not married, even when they have children. I'm actually very happy by myself. And I think if I'd had a partner and he'd seen the risks I've taken financially to get this thing on the road, he would have tried to stop me.'

What strikes me as odd about Katharine Hamnett is that she seems, on the one hand, fearless - fearless about her finances, her reputation, her personal safety - and, on the other, full of global anxiety - about nuclear waste, about anthrax, terrorism, pesticides; almost anything you care to name. But the explanation comes when she talks, with tears in her eyes, about the two great tragedies in her life. First, her father committed suicide, by hanging himself, when she was 28. 'And if somebody kills themselves, you know, everybody blames themselves for ever.' And then she lost her younger brother, Giles, in a motorbike accident when he was 33: 'He was 6ft,6in, totally social, unbelievably adored. Ten people came up to me at his funeral and said, "Giles was my best friend and he was the sort of person you think that nothing could ever happen to" - and he was just killed on his way to work one morning. And when someone is taken very young you miss them forever. I think if you've had terrible things happen to you, it does make you realise how fragile it all is.'

She has no plans to retire, ever, but her ambitions now are way beyond clothes. 'I want to build a concentrated solar-powered, low-tech power station in Africa - I'm very excited about that. Reforesting the desert is another plan that I think is now possible with concentrated solar power.

'I've always believed that you can go up in any profession and then go across, so I'm in the process of doing that, and I think I'll do it till the day I drop.' If anyone else said this I'd think they were barking. Actually I do think Katharine Hamnett is barking but, on the other hand, her success in getting organic clothing into Tesco suggests that maybe barking is not a bad thing to be.