Skinny jeans have been ubiquitous for a decade, worn by everyone from pop stars to politicians. So what is the secret of their success?

Once you start seeing skinny jeans, it's pretty hard to stop. And the more you see of them, the clearer this becomes: the jeans might be narrow, but it's a broad church living in them. Sloanes like them high-waisted, apparently having ironed the legs; emos wear them flatfooted and belted. Hipsters roll the ankles and prefer an imprecise crotch; skaters like them with sneakers and a snapback. You can play this game on almost any street in Britain. If there are people, there will be skinny jeans. They are as much a part of street furniture as lampposts – but narrower.

Cheryl Cole. Photograph: Most Wanted/Rex Features

How did skinny jeans come to hold us in such close grip? For all their bad press about being only for skinny people (admittedly, their name has not helped with this), skinny jeans are in fact benignly elastic and surprisingly democratic, stretching comfortably to include all shapes of bottom and all social groups. They clothe the entire cultural spectrum, up to and including the next queen of England; all kinds of sexy, from Russell Brand to Nigella Lawson; and every musical genre from Lil Wayne through Justin Bieber and Girls Aloud to BBC2's chorister-in-chief, Gareth Malone. (The Lil Wayne end of that spectrum so outraged hiphop artist DMX that last year he gave an interview from prison in which he railed against them as "baby clothes".)They are daytime and night-time, everyday primetime, from Mel and Sue on The Great British Bake Off through Jewish Mums of the Year and Kevin McCloud to Fiona Bruce on Antiques Roadshow.

Samantha Cameron in skinny jeans, with David at the Conservative party conference. Photograph: Oli Scarff/Getty Images

They have become the first choice for first women, as testified by Samantha Cameron at the Conservative party conference last autumn and Michelle Obama. But they also clothe a good deal of the Occupy movement, not to mention Pussy Riot; there are pictures of Syrian rebels in skinny jeans. In Britain, mums on the school run wear them; so do their children at weekends. There is no lower age limit, just as DMX said: at Gap the smallest size of skinny is 0 months. Things do tail off at the other end of the spectrum, although "tailing off" is probably not how Ronnie Wood, 65, Karl Lagerfeld, 79, and former Conservative MP Teresa Gorman, 81 – all skinny jeans wearers – would see themselves.

"The punk revival has to have been the beginning of it," says Jane Shepherdson, the chief executive of Whistles, which lists 14 styles of denim on its website, all of them skinny. "I was a big Clash fan. That's when I wore them the first time around. I remember them getting narrower and narrower and thinking I could hardly get my feet in."

Sid Vicious and Nancy Spungen. Photograph: Redferns

These days Shepherdson owns 15 pairs. Pair number 16, in leather, will be joining them soon. "It is very hard to see us going back to wider jeans. If I could say there would definitely be one thing in the next [Whistles] range, it would be a pair of skinny jeans. I'm sitting in a taxi now," she says, "looking out the window, and the vast majority of people on the Euston Road are wearing them, men and women – all wearing them differently, but all wearing them."

Shepherdson knows a thing or two about skinny jeans: in August 2005, as the brand director of Topshop, she brought them to the British mainstream when she launched the Baxter style. Her tenure coincided with the store's absolute domination of the high street midway through the 2000s: the Baxter averaged weekly sales of 18,000 in its first nine months (although it has since been overtaken by the even narrower Leigh, 1.2m pairs of which were sold in the last financial year).

Shepherdson thinks the punk connection "might explain why skinny jeans are so appealing to the British", but that doesn't really nail their origins this time around. She has a theory that Alexander McQueen's bumsters, first shown in 1996, got us thinking about more interesting trouser shapes, and that an appetite for something different seeped into our consciousness alongside a fatigue with leggings, creating the perfect conditions for skinny jeans to flourish.

Teddy boys in 1972. Photograph: Evening Standard/Getty Images

There are other theories. "You can trace the skinny fit right back to the mid-18th century and a youth movement called the Macaronis," says Sarah Niblock, a professor at Brunel University who specialises in visual culture. "They were the first British fashion movement to use fashion to be subversive. They used to wear very slim-fit clothes." Niblock thinks you can draw a line from the Macaronis through cowboys, teddy boys and punk to now. "That narrow cut is very much about the outsider, about singling yourself out as somebody different."

"Skinny jeans are such a convenient shorthand for youth and rebellion," agrees Rod Stanley, the former editor of Dazed & Confused magazine. He cites Hedi Slimane, whose slim-silhouetted collection for Dior Homme was shown 10 years ago this month, and who is often credited with the narrowing of our perspective and the fetishisation of skinny trousers. Not least by Slimane himself, who was photographing the scene at clubs such as the Rhythm Factory and the George Tavern in east London around this time, and dressed Pete Doherty when Doherty was with Kate Moss.

Kate Moss. Photograph: Richard Young/Rex Features

But there had been earlier signs of tightening trousers. Earl Jean offered slim straight-legs in 2001. In her autumn/winter 2002 collection, Stella McCartney showed trousers drawn taut by cuffs and zips and stirrups. There were stretchy legs at Versus and slim ones at MaxMara. And in December 2002, Ramones fan Lucy Pinter was filing the paperwork to register her company Superfine. Within months it would be dressing Kate Moss in all those faded grey skinnies. Working as a stylist, Pinter had been desperately trying to narrow her models' trousers: "Literally down on my knees wih the black gaffer, taping the bootlegs into skinnies."

By mid-2003 Vogue was hailing "drainpipes", and The Strokes, synonymous with sharp trousers – though only Nick Valensi was wearing skinny jeans at this point – were the height of New York cool. "Every kind of cultural element was pointing to skinny jeans," says Sarah Harris, a Vogue fashion features writer known for her passion for denim. She says she wears jeans 99% of the time and has 30 pairs "in constant rotation", 20-25 of them skinny. "But even then I am surprised that they've lasted this long."

So why are skinny jeans still going strong? A benchmark product of fast fashion, skinny jeans hit their stride just as the British high street became cool and celebrated. Yet they have actually proved remarkably … slow. How come? Perhaps the answer lies in the place with the greatest density of skinny jeans a square metre.

"You would have to say Camden," says Shepherdson from that cab on Euston Road. "Camden market," says Harris, from the offices of Vogue.

Justin Bieber. Photograph: Gregg Deguire/FilmMagic

Two middle-aged guys in dapper hats are sitting on a canal towpath, their legs – one pair in red skinny jeans, one in blue – dangling over the edge. Beside them, some cans of beer and a tin of Café Crème tobacco. They seem to be performing the same job as one of those statues of seafarers found at the entrance to harbours: welcome to Camden, skinny jeans capital of the UK. One of them gobs into the water.

The snackers at the nearby food shacks are all in skinnies and the shoppers are too. So now for that game. It's 2.04pm on a Thursday, outside the Cold Steel Body Piercing shop on Camden High Street. In the first minute, 14 pairs of skinny jeans go past. Another 40 pass in both directions over the next three minutes. Then another 44 in two minutes. Over the next four minutes, 72. That's 170 in 10 minutes. If this average were to hold, more than 1,000 pairs would cross this shopfront in an hour.

Among those passing is Haleema Kukoyi, 24, who bought her jeans in Evans, the plus-size shop. Contrary to the instinct that skinny jeans give the self-conscious nowhere to hide, she likes them precisely because she has "weird-shaped legs and these work best for me." Ron Castisimo and Ash Alcaide, both 25, like them because they are skaters and they listen to "stuff like the Gallows, Trash Talk, the new wave of hardcore."

Aminah Abdullah, 17, from Cologne, wears them "because they make your legs look skinny", even though her mother doesn't like them. "We're Muslim," says Reinhild Buer. "The skinny jeans look great but I don't think they should wear them – only around women."

Donna Watson, 26, and Ross Callender, 25, are both in smart, dark skinnies. She is a marketing manager for The Chimes shopping centre in Uxbridge, and he is a marketing manager for an insurance company. Can their marketing expertise explain the success of skinny jeans?

"It's the rebellion against modern times," says Ross. "It's the middle finger to popular culture." He looks around. "But inadvertently it's become popular culture."

Witness Hayley Carruthers, 42, who bought her first pair last week. Why? Why wait all these years and then take the leap? "It's fashion, isn't it?" she shrugs.

Of a kind. Skinny jeans are less a fashion choice than a default setting. We have come to see them almost as a blank canvas, a piece of clothing that has ceased to signify anything; come, in fact, almost not to see them at all.

It is this invisibility that has enabled them to act as the vehicle for countless other mainstream trends of the past decade, the silent partner to a succession of high-fashion looks. First they tucked neatly into boots early in the decade, when boots were all that women wore, or worked well with Converse when Converse were all that men wore.

Balmain. Photograph: Rex Features

It was skinny jeans that made ballet pumps prolific, fetishising that little scooped-out bit of foot between shoe and hem, and later, with their cleanness at the ankle, acted as a curtain-raiser to hefty statement shoes. They gave extra spike to handbags with hardware in 2006 and their narrowness at the ankle supplied the perfect counterpoint to those pointy shoulders that Balmain produced in 2009. Without skinny jeans there would have been no peplums.

They were one half of double denim, and, chameleon-like, have changed their livery in keeping with fashion, morphing into high-waisted jeans, ripped jeans, embellished jeans, leather-panelled, corduroy, patterned, cropped, tattooed and coloured jeans. They even swallowed up leggings into jeggings and shrunk the language of other clothing too. So scarves became skinny scarves. Thin ties were skinny ties, stilettoes skinny heels. There are such things as skinny sweatpants.

And yet this ubiquity appears to do nothing to dent their popularity. This is not usually how fashion works.

Carol Vorderman. Photograph: Beretta/Sims/Rex Features

When Carol Vorderman wore Roland Mouret's Galaxy dress in 2005, at the height of its A-list acclaim, she killed it as high fashion and he had to invent the Moon dress to give fashionable types some distance. But when Carol "the style goddess", as the Daily Mail calls her, wears skinny jeans, nothing happens (except in the Mail, which wonders whether they're age appropriate: she is 51 after all). No one casts aside their skinny jeans and decides that time's up (if it stopped you wearing yours, drop us a line). Not even the Duchess of Cambridge, in pristine unwrinkled royal blue skinnies at the Olympics, put anyone off. They are still going strong, and the ultimate proof of that came when Slimane made his return to fashion last October after a five-year break. You might think that fashion would have moved on. But his first look was a pair of fiercely narrow black pants.

Skinny jeans are open to all, and no one who wears them makes them any less of what they are for anyone else. The truth must be that there is something about the meanness of this look that feels right for our times. It can't simply be about rebellion – why should tightness seem inherently more rebellious than expansiveness? (Anyhow, if you really wanted to rebel right now, you'd wear bootlegs.)

After all, people felt they were checking out when they were wearing flares, arguably the last mainstream trend to have had the longevity and reach of skinnies. But while flares wafted, got in the way, implied leisure, somehow in skinny jeans we're all hard at something. They are lean jeans for lean times. They cut no slack, suggest hard-upness, partly because the pockets are so impossible to get your hands in. Shrink the word "skintight" and you get "skint".

For manufacturers, skinny jeans make perfect economic sense, requiring less fabric than more generously cut pants; for consumers, their ongoing domination keeps the rest of the wardrobe working too: no need for a costly revamp. (Wait until wider trousers come back, and see how wrong all your other clothes look.)

"It is a bit like wartime, not wanting to waste fabric and resources," says Niblock. "And in hard times people do tend to have a shared sense of identity. You couldn't associate skinny jeans with white fashion or black, young, old, straight, gay."

Maybe it's the tight squeeze of modern life summed up in a pair of pants, all these attenuated trousers painting us as lean and beleaguered as Lowry's matchstick figures (though his wore wider jeans), slender smudges or shadows on a domineering landscape. Or maybe it's their very democracy and ubiquity that's driving on skinny jeans at a time when society feels so cracked and fragmented: it doesn't matter that everyone is wearing them. Perhaps it even feels good. It might not be possible to say this about much else right now, but when it comes to skinny jeans, at least we are all in them together.