For Levi's read Dolce & Gabbana; for Lee read Kenzo. For pounds 50 read pounds 265. For cowboys read bank robber s. As Calvin Klein might have said, nowadays nothing comes between you and your jeans ... except bankruptcy.
In December 1995, say the market researchers Mintel, only 9 per cent of men and 5 per cent of women dared to spend more than pounds 50 on a pair of designer jeans, leaving the majority to buy the more reasonable Levi's, Lee or Wrangler. Just over a year later those figures have doubled: 10 million or so of the 60 million pairs of jeans striding around this country are from fashion designers.

Designer jeans are not new; Calvin "nothing comes between me and mine" Klein has been selling his for 19 years. But these days a trip to your local designer emporium could leave you wondering whether you had strayed into a jeans shop. Yves Saint Laurent, Katharine Hamnett, Paul Smith, Christian Lacroix, Armani, Versace, Gianfranco Ferre and Kenzo jeans are all available across the UK, and more new lines are appearing. If a pounds 600 suit by the Austrian minimalist Helmut Lang is beyond your reach, don't worry; now you can buy his jeans, with the option of huge turn- ups (the ultimate jeans fashion statement), for only pounds 75. Dolce & Gabbana too dressy for your tastes? Not a problem. Stefano and Domenico offer a complete lifestyle package for men and women with their Jeans Dolce Gabbana collection.

Where Klein and then Armani in '81 and Versace in '91 first trod, with logos on otherwise straightforward jeans, others are following - but this time in style. There is no "Helmut Lang" branding anywhere on his jeans range, just a discreet strip in the back of the collar. The designer's handwriting comes with the styling. His jeans are extra long, (for the big turn-up), and slim-cut; pencil skirts come with a flesh-coloured slash insert, and black jeans and denim jackets have a satin turn-up. The most obvious Lang gesture, however, comes in the form of a little wrap (a bit like a bandanna) slung around the top of the jeans and secured with a key loop.

Browns Focus, the new unisex shop on South Molton Street, is selling Lang, Dolce Gabbana and Japanese Evisu jeans, and can't get enough of them. Robert Finnegan, the buyer, is constantly surprised by what youngsters are willing to pay for jeans. "Some Evisu styles cost pounds 265, and there is always a waiting list for them," he says. Finnegan has also found a different set of customers for each label: "the kids who buy Dolce even leave the swing-tickets on their jeans; it's ridiculous, really."

In 1985, when Levi Strauss relaunched the 501 with the famous launderette advert, jeans sales were at an all-time low as most fashionable types went shoulder-pad and power-dressing crazy. Now, Levi's, with the biggest share of the market, are trying to make their product more desirable, (though you can now buy them in Tesco), by reissuing old styles to keep up with the dark denim enthusiasts. But, according to Rokit, a vintage clothing store in Camden Market, London, which sells Levi's by the ton, sales have dropped by 25 per cent in the last year and old Calvin Kleins and more obscure labels such as Lois and Gloria Vanderbilt are in demand. "We only sell Levi's to the tourists these days," says a spokesman.

Seasonal collections from designers often date quickly, but a pair of jeans or a jacket can be worn for years. Most people have a favourite pair: the ones that fit and fade well, are comfortable, easy to wear and timeless. They are like best friends. Designer denim should have the same appeal, but in reality the main appeal is in the marketing mix.

Katharine Hamnett and Versace jeans ooze sex appeal (just look at the advertising - all sex gods and goddesses lounging around), whereas Armani is a bit more demure (wear yours with a linen jacket and some classic loafers). John Rocha's jeans, launched last summer, are trendy and arty (again, see the advertising, all fresh-faced, intelligent types) and Lang's are for modernists. It's all a far cry from the 19th-century labourers for whom jeans were originally inventedn