Diesel's designer denim is in great demand. Now the label has opened an emporium in London selling much, much more. Photographs by Sheridan Morley
When Jarvis Cocker was arrested at the Brit Awards, he had one consolation for spending a night in a prison cell. He was wearing a quilted nylon jacket by the Italian jeans and workwear company Diesel. Last month, the pop star returned the favour by opening the company's flagship store in London's Covent Garden, singing the praises of the jacket that kept him warm through a long, cold night, and also rolled up to make a comfortable pillow.

You might not be familiar with Diesel jeans but you've probably noticed their adverts - irreverent takes on fashion advertising usually featuring flying saucers or cheesy scenes from American high schools - in magazines and on the London underground. One image, in particular, was under scrutiny by the Advertising Standards Authority recently after complaints that it was sexist. Diesel insisted that the ad was ironic and the adverts have been allowed to remain.

The "high on visual impact, low on product" adverts began to appear in the British style press at the end of the Eighties, when Diesel first entered the UK market. Until last month, Jethro Marshall, the UK marketing manager, was having to field endless phone calls from people eager to buy the merchandise they were seeing in the adverts, but not knowing where to buy it. Now that the label has its own shop, in a three-storey former banana warehouse on the increasingly busy Neal Street in Covent Garden, there is a focal point for shoppers to go and see the whole Diesel concept. The brand is also sold in 300 outlets around the country. It has become especially popular in Liverpool, Manchester and Glasgow. You need only walk down the street to spot people wearing Diesel jackets or wraparound sunglasses, typically worn perched not on the nose, but on top of the head like a headband.

The sunglasses alone have become something of a cult. They are easily identified by the holes drilled down the metal arms of the sunglasses. Such is their success that they have been prone to copycats, and cheap replicas are available from market stalls. To keep one step ahead of the copyists, Diesel has changed the round holes to square.

Diesel is the brainchild of one 40-year-old man, Renzo Rosso, the son of a northern Italian farmer. Rosso has total control over the company and its image and his ambitions are limitless. His most recent venture is in Miami where he has just opened his first hotel, the Pelican, complete with kitsch interior - a Rosso trademark. A second hotel in Miami is also being refurbished.

After a spell at textile college, in 1978, Rosso became part of a collective called the Genius Group. In 1985, Rosso pulled out to concentrate on his own project and set up office in his home town, Molvena, at the foot of the Italian Alps. Eleven years later, Diesel has grown into a world- recognised brand, with outlets in 72 countries, from Sweden to Chile. A week before the opening of the London store, a three-storey shop opened on New York's Lexington Avenue, and Paris is next.

The Diesel experience is a bit like the Fiorucci experience of the Eighties: it's bright, it's fun, it's kitsch, it's zany, and it's packed full of clothes, sunglasses, underwear, jewellery, bags and shoes for men, women, and children aged two to 16. If that isn't enough to keep you entertained, there are computers logged on to the Diesel Internet site which is based on the Pelican Hotel, where you can move from room to room, watch videos in the basement, go to the disco bar or talk to other Diesel heads in the chat salon.

This is a store for people with the attention span of a goldfish. There is a men's fragrance, at pounds 10 for a palm-sized plastic bottle that looks like a cigarette lighter. And, of course, there are the jeans, the company's long-term bread and butter - five different styles in 10 different washes. Prices for jeans are around pounds 55. The different shapes include a narrow drainpipe, oversized skater jeans, a comfort cut (for guys with big thighs), a unisex low-slung hipster jean and a straight-legged all purpose, "anti- fit" style. And if finding a pair of jeans to fit can be a nightmare, Diesel has a useful chart explaining their shapes and there is an assistant on hand who makes it his business to help to fit you with the most flattering pair for your body shape.

To keep the brand fresh and current, there is a second line, 55DSL, originally intended as a snowboarding line. Prices are more expensive and the clothes are made in smaller quantities for the more fashion-conscious customer. The range is not sold at the shop, but is targeted at a few independent shops such as Box Fresh in Covent Garden.

According to Mintel, the market research group, brand image is a key factor in the buying of jeans, particularly among the younger age groups. By 1999, the sales value of jeans in the UK is estimated to reach pounds 1.39bn. Diesel is a jeans company with a strong dose of fashion. Step inside the shop and you do not feel as if you have stepped into a denim emporium. The brand is undeniably youthful, although, as Jethro Marshall points out, Diesel does not want to alienate the 45- to 54-year-old age group which is predicted to be the growth area in jeans over the next five years. In order to secure a niche in the jeans market, however, it is essential to find a selling point that does not rely on the American Wild West or Fifties Americana.

Levi's share of the market is untouchable with sales of more than pounds 260m last year. Diesel does not yet figure on the jeans league table in the UK, where brands such as Wrangler, Lee, Pepe and Joe Bloggs lead the way. But with increasing awareness of Diesel's Eurocentric image - references to Swedish saunas (one of the changing rooms), supermarket packaging, flying ducks, and irreverent British humour - the brand looks set eventually to smash its way into the UK's jeans top 10.

Diesel, Neal Street, Covent Garden WC2. For your nearest stockist, telephone 0171-833 2255. Diesel can be reached on the Net on http://www.diesel.co.uk