I stepped through the doorway of the museum, which is lodged in the basement of the Paris headquarters of Chevignon, a French casualwear company; and I took a trip back to the Fifties. It was a treasure trove of treats. There were bright green baseball jackets decorating smiling shop-window mannequins, Ford Benzol petrol pumps lined up alongside immaculate miniature bowling alleys, and red Coca- Cola dispensers on parade next to candy-pink Wurlitzer juke-boxes.

It was the Fifties just the way I remember them, the years of effortless style and pizzazz. When everyone had fun all the time; when you never worried about getting a job, and the sun shone all summer long; when you cruised through town in a chrome-plated turquoise open-top Chevy with tail-fins like a shark's; when you always had a girl on your arm with cherry-red lips and a smile that made your heart ache.

Those were the days. Of course I was not actually alive in the Fifties. I was born in the Sixties and grew up in the Seventies. My vision of the Fifties is a dream vision gleaned from films, magazines, and fashion retrospectives.

Time has turned the Fifties into the American decade. It is now the golden age before Kennedy's assassination, Vietnam, Watergate, and the opening of the Pandora's box of problems associated with modern America.

This idealisation of the Fifties may be simplistic, but it is convincing. Said Amriou, who is the business brains behind Chevignon, the fashion company that has made a mint out of reworking the Fifties, believes we are subconsciously reaching out to a past that is comforting. 'When the future seems uncertain, people look back to the past for something that is more reassuring.'

Oddly, the period we now find reassuring was revolutionary in fashion terms. The concept of the teenager was being born. Instead of growing from children's clothes into smaller versions of their parents' outfits, youngsters began to establish their own dress code. This meant jeans and T-shirts, as worn by James Dean, the man still found on teenagers' walls. It also meant dance clothes - cinched waists, big hair, crepe rubber soles and white socks. Pop music was jiving into existence.

The T-shirt had been merely an undershirt worn by working-class men until Marlon Brando wore it as an outer garment in Tennessee Williams's A Streetcar Named Desire. T-shirts were out in the open by the mid-Fifties: in a celebrated series of photographs, Kennedy relaxes in a T-shirt in the garden of his Washington home. Brando's macho icon was quickly turned squeaky-clean, reinvented as a wholesome, classless product, 100 per cent American - another component of a dream decade.

Jeans sales soared in the second half of the decade. Michael Cooper, 46, deputy chairman of the East European Trade Council, recalls: 'You had to be a very odd character to wear blue jeans in 1950, but there was this extraordinary quantum leap in sales in the second half of the Fifties, inspired by James Dean and Elvis Presley.'

Teenage rock'n'roll girls were no less colourful. They wore full dirndl skirts over layers of petticoats, button cardigans, scoop- necked blouses, white ankle-socks and canvas pumps. The alternative look was Capri pants and chunky sweaters, with breasts pushed forward thanks to ingenious bras, pre-formed and conically stitched or padded.

Ironically, many of those who did not share the enthusiasm for the Fifties in the Fifties have now changed their minds. Lloyd Johnson, owner of the Johnsons clothes store on King's Road, remembers being very unimpressed as a 10-year-old watching Little Richard on television in Hastings, his home town. 'I couldn't understand how anyone would like this character screaming his head off.'

But we keep reliving the Fifties, and each time the decade gets brighter. Johnson, now 47, says: 'When the Fifties came back in the late Seventies, we did it differently. We took peg trousers and did them in madder colours than anything around at the time. The idea was to go over the top in every way.'

Johnsons took the prime products of the Fifties, made them larger than life, and updated them for a new era. The rockabillies of the Eighties wore shoes which had Fifties-style uppers but soles courtesy of Doc Marten. Mr Johnson recalls: 'We put these three dummies with rocker haircuts in the shop window and one day three guys who looked the spitting image of them walked into the shop. They were the Stray Cats.'

Retro groups like the Stray Cats, the Polecats and Matchbox led the rockabilly revival. The new rockabillies hated the predictability of the Teddy-boy look, preferred Johnny Burnette to Buddy Holly, and hung around the Bobby Sox club in Neasden.

Mr Johnson says this period started in 1977 and lasted at least 10 years. 'Vivienne Westwood and Malcolm McLaren gave it direction in fashion terms, selling the rocker look at their shop, Let It Rock.'

A stream of films maintained the momentum. Grease, released in 1978, starring John Travolta and Olivia Newton-John, was a period musical marketed specifically for teenagers, rather than the older generation who had lived through the period. A steady flow of films followed through the Eighties, strengthening modern teenagers' enthusiasm for the decade: Diner (1982), Rumblefish (1983), Back to the Future (1985) and Peggy Sue Got Married (1986).

Now Johnny Suede, a film about a character obsessed with suede and Ricky Nelson, has taken up the flame, although the character of Johnny is clearly of the Nineties rather than the Fifties. Director Tom Di Cillo, aged 32, is too young to remember the Fifties, but he saw James Dean in Rebel Without A Cause when he was 13 - in 1973. The film was made in 1955. It is a neat illustration of how the decade's mythology is passed down the generations.

For in the fashion world, the Fifties continue to influence all levels of the market. Currently, the wardrobes of Fifties' film stars are the inspiration for many a fashion magazine shoot, from Ava Gardner's Capri pants and white shirts to Audrey Hepburn's throw-on little shift dresses.

Fifties fashions may come and go, but the Fifties American teenage attitude has set the tone for the whole of modern youth culture. Four successive decades have embraced rock'n'roll and led to the now standard dress-down wardrobe of jeans and T-shirts, worn in offices and clubs and for Sunday lunch.

In 1992 there are two sets of Fifties' kids: the over-40s who were teenagers during that decade and lived the dream, and those of us under 40 who have lived it after the event, vicariously.

Still not convinced that the Fifties live on? Check out the Elvisly Yours fan club, run from the shop of the same name in London's Shoreditch High Street. Its latest recruit has reached the grand old age of six. It seems we are all children of the Fifties.

(Photograph omitted)