But one of fashion's longest survivors is at last showing its age, and the older it gets, the faster its appeal is fading.

Firstly, the figures are not looking good. Statistics indicate that the jeans market is shrinking.

Levi's are among companies reporting a drop in sales

The research consultancy, A C Nielsen, say that annual jeans sales fell by more than three million pairs in the last year, a slump of 14.3 per cent. In cash terms, this has resulted in a market drop from £609m in 1996/97 to £561.2m this year, and the next few years are predicted to follow suit.

Middle-aged blues

Analysts are blaming it on an image problem. Jeans, they say, are just not considered trendy to the younger population so long as politicians, ageing personalities and middle-aged parents continue to wear them.

In their opinion, there is no better way to alienate a generation of fashion-conscious youngsters than to see Top Gear presenter Jeremy Clarkson sporting a tight pair of denims or Des O'Connor in faded blue jeans and a tweed jacket.

Workwear on the frontier

Jeans have had a lot of wear over the years. Little did Levi Strauss know when he introduced jeans in the 1850s as the hard-wearing attire for gold diggers in San Francisco, that more than a 100 years later, they would influence the wardrobe of millions.

The next to slip into them were the cowboys, but before long Hollywood had shown them in enough films for jeans to be considered the wardrobe for the rough, tough and ready.

Actors like James Dean, who starred in the Rebel Without A Cause, and the seductive Brigitte Bardot influenced the look and the attitudes of young people at the time.

Changing times

Through images like theirs, the blue jeans became synonomous with rebelliousness, danger, and most of all, a generation fighting to break away from conformity.

Jeans continued be adapted to the times. In the hippy era, they became plastered with embroidery to suit the flower power generation.

In the height of the Cold War, jeans symbolised the gap between the Western World and Soviet bloc countries, for whom this most widely-available consumer item in the West was near nigh unobtainable.

Diana, Princess of Wales, in one of her more casual poses

The casual denim look worn by Britain's Prime Minister, Tony Blair, and US President Clinton when they met last year in Denver, Colorado for the G8 summit, suggested jeans were acceptable and respectable attire for anyone from builders to powerful politicians.

In and out of fashion

A decade ago wearing the right jeans with the right fit was portrayed as a serious matter. Marketing jeans required showing hunky male models stripping off in launderettes or sitting bare-chested in baths to shrink their jeans to fit.

But now, according to the market research group, Mintel, companies like Levi Strauss and Wrangler are aware that the market among 15-24 age bracket is dwindling and they are adapting their advertising campaigns to appeal to an older generation.

Levi's have launched new range of chino-style Dockers trousers, which Mintel says is doing very well among the younger market.

In some offices, jeans are now acceptable apparel

High-profile sportswear labels, like Nike and Adidas, are stepping in to fill the casual wear scene with tracksuit bottoms and sweatshirts embossed with their name and logo to appeal to the label-conscious.

But manufacturers and style pundits will have a hard time finding another garment with similar universal appeal and lasting power as blue jeans.