FASHION, said the Austrian designer Helmut Lang, is about attitudes, not hemlines. He should know. As one of the masters of minimalism, his pared-down style in the 1990s epitomised a desire for simplicity. Minimalism brought trousers stripped of fussy pleats, fabrics stripped of fussy design, and floorboards just stripped to create the sleek, sharp look that defines urban chic.

Reflecting the prevailing mood was for many years pretty much as far as planet fashion ventured into the orbit of ordinary life. But in the past decade that has decisively changed. Since the late 1980s, fashion designers from Dolce & Gabbana down have been engaging with a range of gritty issues by supporting charity campaigns raising both funds and awareness. Everything from breast cancer, Aids, and disaster relief to conservation and animal protection has had its designer supporters. Supporting charity is the very much in fashion.

In the latest such collaboration, nine top designers are today having their work launched on the internet auction site ebay in aid of the Red Cross Afghanistan appeal. Julien Macdonald, Dolce & Gabbana, Michael Kors, Antoni & Alison, Sophia Kokosalaki, Tracey Boyd, Tanya Sarne at Ghost, Betty Jackson, and Cozmo Jenks have each taken a single classic white Thomas Pink shirt as their blank

canvas and have customised a design specially for the auction. Their images are on show in this month's issue of the fashion bible, Elle, and in the windows of Thomas Pink's stores in Edinburgh and Glasgow.

The high-profile auction is one of the most impressive examples yet of the charity-fashion interface which has been red hot with activity since September 11 when the world's fashion set, in New York for fashion week, were rocked by the attack on the World Trade Centre. Fashion week was cancelled and at subsequent shows in Europe there was an outpouring of love for the city by designers such as Dolce & Gabbana in Milan who had their models wear red, white, and blue NY souvenir T-shirts. According to the acting editor of Elle, Margi Conklin, it has become cool to be political. ''It has become quite a trend to be involved with charities or politics and have opinions about what's going on in the world,'' she says. Designer du jour Julien Macdonald, describing his lace and sequin confection for the Red Cross, suggests it is ''just what the world needs right now'', adding that the Red Cross, who

worked tirelessly first at Ground Zero and now in Afghanistan, is ''one thing I do still believe in''.

But the history of fashion's involvement with charity campaigning and more political forms of protest goes back much further than the past few months.

The first rebellious offspring to be produced by the marriage of fashion and campaigning was the slogan T-shirt. It was championed by the CND-supporting designer Katharine Hamnett in 1984. Hamnett turned up for an audience with Margaret Thatcher wearing a giant shapeless white T-shirt bearing the slogan ''58% don't want Pershing'', in reference to nuclear missiles the government was thinking of accepting on to British soil. The idea caught the imagination of charities. Designers were recruited early on by a few - WWF got David Emmanuel, Princess Di's wedding dress designer, to design a large T-shirt featuring a tiger for its 1986 Christmas catalogue. But by the mid-1990s the idea had become as washed-out as many of the garments themselves. Then Ralph Lauren stepped in. Lauren was inspired in a Geldofian way to galvanise his industry for the good after a close friend, Nina Hyde, the fashion

editor of the Washington Post, died of breast cancer.

Lauren enlisted the support of the Council of Fashion Designers of America, representing 200 US designers, for a campaigning T-shirt. The T-shirt, fashion- ably tight-fitting and cap-sleeved, a welcome break from the Greenham Common-style smock look, was designed by Lauren himself and publicised by supermodels. Thousands were sold. It was, as it were, a runway success.

By tapping into the recession-proof rain-or-shine passion that young women have for their clothes, a massive (pounds) 3m has been generated in the UK by the T-shirt since Breakthrough Breast Cancer imported the idea in 1996. After campaigns in 1996, 1998, and 2000, the latest T-shirt will be launched in April.

A good T-shirt raises awareness among its target audience as well as money. A Toby Mott version bearing the Marie Curie ad slogans like ''Love you to death'' instead of the usual ''I haven't got a thing to wear'' was modelled by Kate Moss for Marie Claire last year, highlighting the charity's work among young women. The Red Cross venture with Elle performs a similar function as David Dunn, head of marketing for the charity, explains: ''Like all charities, we need to attract our donors of the future and this is an excellent way for us to reach a new audience.''

But the fashion-charity love-in has developed far beyond the stretchy confines of jersey fabric. Fashion Cares is a wonderfully camp fund-raising venture driven by Canada's top designers. Raising money for Aids charities, it started as a risque fashion show but, over its 16-year history, has become a lavish gala event attracting 5000 people. Supermodels like Claudia Schiffer are regulars and the fashion industry's darling, MAC Cosmetics, became its main sponsor in 1994. All proceeds of MAC Viva Glam lipsticks go to the charity. But the latest vogue is for the Red Cross-style auction of exclusive designs. Last year, mobile phone covers designed by DKNY, Anya Hindmarch, and Ghost went under the hammer in a virtual auction raising more than (pounds) 5500 for the Terence Higgins Trust. Last year, a Ralph Lauren-sponsored auction at Christie's raised (pounds) 180,000 for the Lighthouse Trust.

Even princess plastic, Barbie, has had her exclusive clothes by Stella Mac, Versace, and Paul Smith auctioned in support of the Elton John Aids Foundation.

The advantages for charities are clear. But what about the designers? For an industry which is notoriously self-obsessed, the current vogue for wearing hearts on sleeves inevitably arouses a certain amount of cynicism. A charitable project generates priceless advertising and PR. Fashion insiders are not immune to guilt, counters Conklin. ''People who work in glamour are aware that they are not involved with the most difficult issues in the world,'' says Conklin. ''Post-September 11, even fashion magazines are more interested and impassioned about what is going on in the world.''

Personal crusades mark out the charity work of several designers, like Ralph Lauren and Stella McCartney. McCartney has staged fashion shows in support of research into breast cancer, the disease that killed her mother, and, as a committed vegetarian, has continued to eschew fur on the catwalk.

There are some exceptions. Naomi Campbell used to be a spokesperson for People for the Ethical Treatment of Animals (Peta). She featured in a poster saying ''I'd rather go naked than wear fur'' only to appear on the Milan catwalk in March 1997 wearing a fur coat. As for Katharine Hamnett, that anti-nuclear firebrand, she has now announced her support for the

Conservative Party.

Ultimately, though, the question of why is not important. The crucial point is that the relationship between fashion and charities has been hugely successful in raising both awareness and cash. Signs are that the current vogue for a social conscience will turn out to be permanent.

Thomas Pink's nine exclusive designer shirts are being auctioned for the Red Cross Afghanistan appeal on ebay from today for one month. The highest current bid for each shirt is visible. The website address is www.pages.ebay.co.uk/charity/