Stephen Bayley: A four-letter word with sexual connotations we can all shout about: M-i-n-i

The Mini has that covetable quality that defines all successful products. See one and you want to own one.

The Mini has that covetable quality that defines all successful products. See one and you want to own one. It is a car that has changed patterns of social behaviour, given a word to the langauge, defined a type and an age. And, you know, this applies as much to the 1959 original as to the current car, just given the accolade of Car of the Year at the International Motor Show in Detroit.

Younger readers may need it explaining that there are two Minis, equally impressive, almost totally different. The earlier one predates even Philip Larkin's discovery of sexual intercourse, the Lady Chatterley trial and the Beatles' first LP. The latest one exists in a very different world. Only the name connects them, but a comparison of the two is richly revealing of how Britain has changed in the past 40 years.

The 1959 Mini was a turning point in the history of design: one of the most original and influential machines ever made. How something so radical emerged from the stultifying culture of Longbridge and Cowley is a mystery, but the Mini was a revolution. Front-wheel drive, a transverse engine with a gearbox compactly located in the sump and advanced suspension were combined for the first time to make a brilliant automotive package providing astonishing accommodation inside a tiny envelope. Within this envelope it was awesomely Existenzminimum. The windows slid (horizontally) and there were string pulls for the handles leaving the doors empty of winding gear, so you could store glass milk bottles there (mineral water had not been invented). Never before had anyone designed a car from the inside out and, just for once, form actually did follow function.

While the Mini was certainly a symbol of Britain, it was also a symbol of amateurishness as much as genius. It is sad, but true, that while the Mini was successfully imitated by Renault, Toyota and Volkswagen, the costly-to-make vehicle bankrupted the native British motor industry. Which is how we got here: the new, award-winning German-owned Mini is in fact a small, camouflaged, front-wheel drive BMW made in Oxford.

Some people were disappointed by BMW's efforts at first, saying the new Mini was a striking concept but seemed bloated and overwrought, a travesty of Alec Issigonis's purist intentions. But as soon as they drove it they were converted. It preserves the good bits of the original conceit and has subjected the rest to the ferocious and unbending scrutiny of BMW engineering and quality control.

The old Mini was marvellous to drive, offering dynamic sensations on the road which anticipated the social and cultural liberations of the Sixties to come. It is not true that the new Mini goes as well as the old: it goes far better. The 2001 Mini feels wide and stable; front passengers do not get the impression that they are in a small car, and the driver does not have to struggle with an atrocious driving position. DIY heating, a corrugated ride, crude electrics, gaps, rattles and leaks have in the new car been replaced by every modern comfort and convenience: even the back seat is survivable. While in 1959 you sat with your neck bent, your face in your lap and your knees in your armpits, it is a measure of progress that today provision is made for you to accommodate your triple skinny latte. One brilliant design detail (which people will not notice, but will enjoy) is that the doors, in the interests of dignity and elegance, open nearly 90 degrees.

Consumer psychology is a very imprecise science, but here you have a brilliantly executed adventure into it. The Mini is a synthesis of genius. A German car whose unique selling proposition is its kinship to a British model dating from 1959 would confound many MBAs, although they would appreciate the reasons why the new car costs up to £16,000 while its predecessor sold for £448. The old Mini was the first car to become classless; its modern version is not exactly sexless but it is free of gender associations. Neither weedily effeminate, nor wince-makingly butch, it has universal appeal, from Chelsea, London, to Chelsea, New York. It is a brilliant product: Mini is a four-letter word that – for the second time – defines a way of seeing the world. In fact, the old car and the new one have more in common than I first thought.