They're also a way of people aligning themselves to a cause. 'Slogans work on so many different levels they're almost subliminal. 'I wanted to put a really large message on T-shirts that could be read from 20 or 30ft away,' she says now. Hamnett's T-shirts became cultural signposts to the times we lived in. Wham! wore a T-shirt with the slogan 'Number One' - and later 'Choose Life' Frankie Goes to Hollywood had 'Frankie Says Relax'. Hamnett's designs were copied all over the world. (The slogan referred to public opposition to the basing of US Pershing missiles in the UK at the tail end of the cold war.) Dressed in a '58% Don't Want Pershing' T-shirt, she was photographed shaking hands with the then prime minister Margaret Thatcher at a Downing Street reception for London fashion week designers in 1984. In the 80s, slogan T-shirts reached saturation point because of one woman: Katharine Hamnett. 'The DIY ethos meant that many people made them at home.' 'Westwood made the aesthetic available to a lot of people in the 70s,' says Sonnet Stanfill, fashion curator of the V&A. McLaren called it 'the ultimate punk-rock T-shirt'. In the 70s, shock tactics prevailed: Vivienne Westwood and her partner Malcolm McLaren made political T-shirts to sell in their shop, SEX, and the most popular design featured a swastika and an inverted crucifix under the word 'Destroy'. Its Disney designs, which included images of Donald Duck and Mickey Mouse, were quickly snapped up. The first slogan T-shirts were sold by Mr Freedom in the 60s, a shop on London's Kings Road set up by Tommy Roberts and Trevor Myles. Of course, the T-shirt has long been a means of telling the world what we care about. Witness Katie Price last week in a T-shirt that read: 'Save a horse, ride a cowboy.' One can only hazard a guess at what Peter Andre might have got from that. But trends in T-shirts do change, and right now, it's all about the message. Like jeans and the little black dress, the T-shirt is a fashion item that has gone beyond fashion.

Frankie says relax tee