Appearance: Something like a seat of geometric fig leaves painted on by a prudish, medieval pop artist under the influence of LSD.

Date of birth: As the name suggests, the garment first appeared in 1946, soon after the US military exploded a nuclear device near the islands of the Bikini Atoll. That is to say, this year is the bikini's 50th birthday.

It was lucky the suit was not named the atoll, which would have given rise to bad jokes about its fans wearing nothing atoll: Indeed. For that piece of good fortune you can thank a Frenchman called Louis Reard.

Did you say "Rear"? How apt: Actually, the name is pronounced Ray yar, and you have now used up your daily allowance of bad jokes. Ray yar had been a civil engineer, but later joined his mother's hosiery business, where he clearly felt more at home.

So it was M. Ray yar's interest in civil engineering that led him to choose a name with such unpleasant associations? It wasn't his fault. The swimsuit market had already been sent in the nuclear direction by a competitor of Reard's, Jacques Heim, who had earlier produced a two piece bathing suit which he called A tome. Heim advertised his garment as "the world's smallest bathing suit". Reard countered that his creation was "smaller than the world's smallest bathing suit" and clearly won the day. What the activities of both men suggested, however, was that the business of making swimsuits that covered less was already a burning topic among those whose minds were not on the second World War.

Among whose number was M. Reard? Well, not necessarily. Early models of the garment from Reard's studio were made - in good neo Cubist style - of fabric over printed with newspaper text, presumably featuring stories about the war. By the time he first showed the bikini - modelled by "Casino de Paris stripper Micheline Bernardini - to the public, it was of a more, decorative nature.

This was presumably the woman responsible for the popularity of the garment? Although Bernardini enjoyed brief celebrity . . .

So you're doing the jokes now? ... in France, it was not until Brigitte Bardot wore one in And God Created Woman in 1956 that its success was assured. From that point on, every few years would see a starlet making a bid for celluloid immortality with a bikini scene. Among the highlights were, of course, Ursula Andress's arrival on the beach in Dr No, and Racquel Welch's Cromagnon number in One Million Years BC.

But that all was years ago. Is there a big future for this small item? Sales of bikinis have certainly been declining as a proportion of total swimsuit sales, even if 52 million sets were sold last year. As well as the obvious stupidity of opening up so much skin to the death dealing rays of the sun, it's also hard for a 50 year old to make out on the beach at Baywatch. The lifeguards there, you will recall, wear sporty one piece suits. If that wasn't enough, there is the Olympics, which have probably ensured that bikinis will swiftly be replaced by all in one bodysuits constructed of revolutionary new, low friction polymers. After all, what is the point of swimming if you can't look like Michelle Smith?