Skinny: The look with endless legs Worn by the squeezed middle and the super-rich alike, the 'skinny' trouser has become the silhouette-defining garment of our time. "The skinny pant," says Jeff Rudes, "is here to stay. No matter what else is happening on the catwalks, it's a bestseller, year in year out. Rudes is the American founder of J Brand - the cult jeans company that last year sold six million pairs, most of them skinny. You could say he's narrow-minded. He's also right. Over the coming weeks there will be no shortage of advice on the key trends for spring and summer - but swathes of women will, as they have for the past 10 years, carry on wearing drainpipes, with a variety of tops (baggy or tight) and jackets (cropped or blazers). Social historians looking back on the early 21st century will conclude that flares, lace, digital prints, metallic and all the other transient headlines were just a side dish. The dominant silhouette is long, lean and built for speed. Its exponents - and there are many - include Liz Hurley, sipping green tea in Gloucestershire in her white 7 For All Mankind jeans; the Duchess of Cambridge walking her cocker spaniel along the beaches of Anglesey in J Brand's navy 811s; Rosie Huntington-Whiteley conducting a master-class in modern aviation glamour in black leather drainpipes; Rihanna giving text-book degenerate diva-style a whirl in cut-out leather Rodarte hold-ups; Mary Portas bestriding the high street in cropped Houlihans (the J Brand style that caused a waiting list sensation in 2010); Fiona Bruce, Kate Silverton and fellow BBC presenters singing All The Single Ladies in their slim black trousers and military jackets on Children in Need in 2009... These women represent the north-south-east-west of taste, yet whether they're on the Waitrose run or the red carpet, they're united in their choice of quotidian uniform. Duchess of Cambridge buys this season's hottest jeans How did such ubiquity occur? For two extremely pragmatic reasons: it works internationally and across weather fronts. Bill Cunningham , The New York Times 's indefatigable octogenarian chronicler of street style, remarked last month that the skinny-covered leg, anchored by a solid ankle boot and some kind of oversized, furry coat, was the dominant look on Manhattan's freezing sidewalks. As the days warm up, the caterpillar-soled high-heeled boots will make way for flat velvet slippers and statement sandals, while the animalistic coats will be replaced by feminine broderie anglaise tops. This is one of the few catwalk trends destined for mass adoption, not least because broderie anglaise is the perfect play-off against a tough jean. There seems to be unlimited mileage. J Brand, widely regarded as a market leader, has coated snake-prints, florals and even multi-coloured tie-dye in the pipeline for summer. Exclusive: First look at Christopher Kane and J Brand collaboration On some level, designers instinctively know that whatever they put on the catwalk, its success depends on how compatible it is with skinny jeans. This is especially true of footwear, 98 per cent of which is now designed to work with a drainpipe leg, hence the enduring popularity of the high-heeled ankle boot and shoe-boot. Yet viewed objectively - i.e. not through the prism of habit - the skinny is a highly suggestive, unforgiving item of clothing. In extreme cases, a tight jean gets gynaecologically explicit. It was Alexander McQueen, in the early Nineties, who reshaped trousers, elevating them from a safe also-ran fashion garment to something much more provocative and subversive. The late Eighties had been all about the sexy power suit, the star of which was a mini-skirt; not a trouser to be seen. The McQueen bumster was masculine and outrageously low-cut on the hips, hence its soubriquet, and narrow. An ocean of whale tails (the evocative name for the visible G-string that was the inevitable result of wearing such a low waistband) was the result, as scores of "premium" denim brands launched to take advantage of the hipsters revival. Rudes went one further when he launched J Brand in 2005. Its first design was a skinny leg - in dark denim. "I wanted something completely different from all those other Californian premium denim ranges," he says. From the start, J Brand was conceived as an aspirational fashion label that would ride out the denim craze. By increasing the rise on his jeans to nine inches, Rudes created a silhouette that elongated the leg, held in the tummy and, by ending just above the navel, created the illusion of a slimmer waist. Kate Moss gave them her blessing and J Brand became a worldwide phenomenon. Niche companies such as Kova&T, a leggings business part-owned by Russian socialite Dasha Zukhova, began selling leather and sequinned leggings on net-a-porter.com for £400 - £500, prices that seemed ludicrously high, but sold out. The same year that J Brand launched, a then 41-year-old Christophe Decarnin started at Balmain, a once-staid house that hijacked the skinny jeans look and transported it to the world of luxury, selling its ripped skinny denim or black leather jeans for £2,000 upwards. Decarnin's vision of modern woman - a futuristic glamazon with long, attenuated legs, encased in shiny or metallic second skin and cartoonishly exaggerated shoulders - was part punk, part preternaturally long-legged insect. French Vogue couldn't get enough of it, and the rest of fashion followed, an evolution not lost on Rudes who, next week launches J Brand's long-awaited ready-to-wear range: masculine-inspired jackets, silk tops and man-tailored skinny trousers. Prices, around £700 for a jacket, an eye-watering £1,500 for soft lamb leather jeans in grey or cream, which, says Rudes, "have been bonded on to stretch fabric so they never bag," confirm that the jean has surpassed any definition of luxury that Calvin Klein or Gloria Vanderbilt might have dreamed of back in the Seventies when they first toyed with the concept of designer jeans. Even if most women won't be spending £1,500, the leather, pleather (fake leather) or coated (shiny) drainpipe - once a staple of the hoary old punk rocker and, before that, a sub-section in the sex shop catalogue - has become a modern classic, from Topshop's £32 line to Joseph's yummy-mummy £600 versions. There's no sign of demand abating. Before Christmas, Zara and Topshop did a brisk trade in metallic jeans - a trend that looks set to last well into 2012. The effect may not always be subtle, but they're unarguably alpha-female. Elle Macpherson's silver leather skinnies and soaring Louboutins caused much abrasive internet discussion last autumn, most of it, predictably, focused on her age - 47. What I'm wearing: Leather leggings But the point about the skinny is that it works for across generations, because, unlike mini-skirts, it reveals shape while concealing skin. In this, it offers an ageless proposition of skinfinity. "Modern fabric technology means any woman can wear them," affirms Rudes. Power stretch, which is what drives our brand, means a pair of jeans now acts in the same way that a girdle did in the Fifties. And it works for every occasion. Wear it with a jacket and it takes you to the office or dinner. Actually, skinny trousers may not be the best choice for every body, but on the right woman, they look almost super-humanly impressive. "So many women look better than they ever have, what with all that gym and looking after themselves," observes Mary Quant, whose championship of the mini-skirt 50 years ago represented a similar marker of female emancipation. Some carp that teaming an almost gymnastic-looking lower half with tailored or feminine tops sends out mixed messages, and that skinnies make younger women look like a praying mantis and older women like cougars (the skinny leg has inspired numerous bestial analogies). But perhaps it's the contradictions that make it the perfect staple for our times. That and the fact that jacked up on to a pair of four-inch heels, or grounded into a pair of biker boots, a pair of stretch, streamlined jeans makes you feel you're ready to take on the world.