The word on the street in fashion's heartland is not one you'd want your granny to hear. Emma Daly on the T-shirts and underwear to be obscene in this spring
You've seen those souvenir stalls in London, dominated by T-shirts with amusing slogans ("My mum went to London and all I got ...") and postcards of sneering youths with green Mohicans? Now designers have come up with a fab idea that combines both concepts: the T-shirt that tells you to Fuck Off!

Obscenity, it seems, is all the rage, particularly as a way of thumbing one's nose at foreigners. "London Says F**K FASHION And the World Buys It!" shrieks Time Out, the capital's guide to what's happening.

The same spirit is in evidence in the window of Browns on South Molton Street, probably the best-known designer boutique in London. Here, a sofa upholstered in "fuck"-patterned fabric has been on display to promote a range of clothing by Hysteric Originals: jackets, trousers (matching), jeans, swimming costumes and underwear are all covered in obscenities.

"There are cute little camisoles in baby blue and pink, and teddy bears, and in between the teddy bears it says `fuck off'. And the same on the underwear," says Lee Godby of Browns.

You'd have thought that if anyone was going to see your knickers and camisole you'd be sending a different message. But then, the designers are Japanese, so perhaps they are more interested in the words as pure graphic devices than what they mean. Browns also sells T-shirts by Anand Zenz with the logo "Fucking Boys and Fucking Girls" and "Blame it on the USA" - this last a bit political, but as Lee says, Anand "is an artist by rights".

This brave new world extends even to the high street, where French Connection has chosen to emblazon its British corporate identity as FCUK on T-shirts and in shop windows. A press officer for French Connection points out that this is not the F-word, merely the acronym for French Connection UK. "When you first look at it, that's what it looks like and we knew that's what it looked like,'' says Lilli Anderson defensively. "It's very light-hearted."

It all seems most peculiar, but fashion experts say it is a reaction to the conformism typified by Armani suits and Calvin Klein tailoring. We've had Alexander McQueen's bumsters and see-through chiffon dresses, so obscene T-shirts are the next logical step, says Lee. He doesn't expect it to last: "I don't think people are going to walk around with `fuck' emblazoned on their T-shirts for ever."

They might grow up, for one thing. We may sigh for those playground days when mention of "Bottom" or "Fart" brought shrieks of hilarity and a frisson of daring, but those who still find it amusing or rebellious to shock grown-ups will have to fork out pounds 45 for a pair of knickers or a vest or pounds 50 for a T-shirt. Now that's obscene