Get this. Pop sox are stylish. It seems impossible, doesn't it - even with fashion's dedication to turning bad taste into new chic. It seems unthinkable that pop sox, for so long a guilty secret hidden under trousers, should surface. But they have.

Blame Linda Evangelista, who wore hers to a high-profile New York party with a micro metallic miniskirt. Blame Madonna, who wore pop sox with a Heidi-goes-yodelling ensemble that someone, somewhere should take the rap for. Blame Calvin Klein, Anna Sui, and Gianni Versace, all of whom took part in the pop sox catwalk comeback for spring.

Many bizarre rebirths happen up on the catwalk, and up there, they also die. Linda and Madonna wear all sorts of numeros that do not catch on. But pop sox have - extraordinary isn't it, except when you realise that those who think these are groovy now didn't live through the time when they were first groovy, then goofy, before.

Think pop sox (some of us have tried not to for many years) and you might think of the Sixties and Seventies. But these nylon nightmares actually entered fashion's lexicon two decades earlier, in a prototype form of wool mixed with cotton. History does not record the name of the boffin who invented them, but the year was 1946; the place, the Wolford factory in Bregenz, Austria; the name Kniestrumpfe; the event, the beginning of a gripping yarn for the legs of the world's women.

Early Kniestrumpfe were grey-black, semi-sheer and the answer to a Fraulein's prayer. Austrian women snapped them up with all the gusto that American dames reserved for a new delivery of nylons. The Kniestrumpfe stayed just the same until the Swinging Sixties reached Bregenz. Then spandex and sparkle were introduced to the mix, and utility legwear became trendy. A new, universal name was needed. Pop meant 'happening' and the spelling of socks became the groovier sox. Everybody wanted a pair.

The hosiery giants Pretty Polly, Aristoc and Golden Lady jumped on the bandwagon and churned out pop sox for an eager world. There were shiny pop sox, psychedelic pop sox - plus that hot favourite from Los Angeles to Luton: Californian tan pop sox. Whatever colour they were, they were the business.

The Sixties style princess Mary Quant remembers: 'We sold masses of them at the beginning, they were terrifically good underneath things.' But she admits that doubts crept in quickly: 'I don't think they were extremely flattering - you got a ferocious line when you took them off, which is why I abandoned them in the end.'

But not before Lesley Hornby, renamed Twiggy after her gawky pins, had encouraged every Georgie Girl that she had to have a pair or three. Sales rocketed. Kids wanted to wear them to school and Mum was wearing them, too.

Not that anyone who was around in the Sixties admits to having liked them when asked today. Cathy McGowan and Lulu remain professionally coy. Both their agents say: 'No comment'. Lynsey de Paul admits she did wear them: 'But they were gross, most unattractive; passion-killers . . . and it felt as if your knees were being strangled.' For that is how pop sox are remembered: not as great and groovy, but as cringe-making. In the same way that a George Best hairdo and a wide tie became daft, so did pop sox suddenly become more goofy than groovy. But although they went out, they didn't go away. Instead, they went underground, hidden beneath full skirts and fuller trousers. They were practical, but what passion killers - an even bigger turn off than purple nylon Y-fronts.

There they stayed, suspected but rarely outed, until fashion felt fit to say they were groovy again. It did. They are.

But there are sub-plots within the story of the return of pop sox. The first and the simplest is a story of technology, of developments that mean Versace can now offer laddery cobwebs of gossamer (for pounds 120 a pair), which are light years on from the shiny, nylon American tan three-in-a-pack for 99p at the supermarket. Hosiery manufacturers now talk dreamily of mesh soft textures and subtle hues and modern pop sox wearers get all excited.

But the second sub-plot has the sting in it. For when one asks: 'Why pop sox now?', the answer has to be 'what else are you going to wear with all that Lolita school kit designers are peddling for spring?' Pop sox are a part of the school- slag-behind-the-bike-shed look, which has grabbed the imagination of too many designers to ignore.

Ah, so that's it. Pop sox are hip again for they are young again. In fashion terms, they are Generation X, while to these people's mothers - the first international customers - they remain a guilty secret. Mrs Average from Accrington is no more likely to admit to wearing them this spring than she was last spring.

And even if she did, what would she call them? New customers happily call them pop sox, but for years this has been a product that dare not speak its name. Euphemisms came into use: knee-hi, knee-hose, Mini-Maxi, below-the-knee, support sock and knee-stay were knee- jerk reactions to pop sox' relegation to oblivion.

But back in Austria, where our story began, the old name held true. Austrians, their heads held high, have always been happy to ask for Kniestrumpfe without blushing. And all the while, Wolford, now an international hosiery giant, has grown fat on the profits. So what does Elmar Bachmann, creative director of Wolford, think of the pop sox renaissance? It's the dot on the company's 'i' - or, as they say in Austria, 'Das Tupfelchen auf dem 'i'.'

(Photographs omitted)