Something old, something new: Rachel Zoe and Kate Upton's favourite vintage merchant makes a play for the 21st century shopper

William Banks-Blaney is a man with a passion for the past and an eye for the future. This week, he launches a website that promises to show old clothes in an entirely new way, with what he's dubbed the "net-a-porter of vintage." Alexander Fury meets him to talk mothballs, returns policies and a hatred of retro.

Rachel Zoe in a William Vintage 1967 Jean Patou dress

Meeting William Banks-Blaney confounds your expectations of a vintage clothing dealer. He doesn't smell of mothballs, for a start; and he doesn't look a single inch retro. Retro is a word he spits out with disdain. "I don't like dress up, at all. Which is why we don't do vintage shoes or vintage handbags," he reasons. "I think it's really important that you don't look like you stepped out of a film, or are on your way to bachelorette party."

He's talking about his store, William Vintage, which I'd hazard to pitch as London's premier vintage destination - or, at the very least, top three. The company was founded in 2010 when Banks-Blaney, 42, ducked out of past incarnations as art dealer, antique dealer and finally interior designer to sell a trunk of vintage clothes to a few dozen female friends and acquaintances. He chose a function room off Sloane Square, and hoped the experiment would recoup what he'd enjoyably spent sourcing the pieces. They sold out, another sale followed, and spiralled into the store and a roster of fans including fashion insiders, celebrities, a cadre of well-dressed, deep-pocketed women and a clutch of international museums who appreciate Banks-Blaney's eye for rooting out past treasures. He searches through his phone to find an image of a remarkable dress, recently sold back to the house who created it to fill a hole in their archives.

Vintage is, of course, a big business, with designers and stylists shredding store rails in rapacious search for the next new (old) thing. The garments will then be incorporated into shoots, or sent to design teams as references for new clothing (incidentally, I know many designers with a rail or two of Banks-Blaney's finest waiting to be examined for collections to come). It's standard practice: fashion has been preoccupied with the past for decades. So long, indeed, that some of those recycles of past hits are now, ironically, being sold back to us - they're old enough to be dubbed 'vintage' themselves.

Kristen Scott Thomas at the 2015 BAFTA awards in a 1948 Balmain gown, from William Vintage (Getty)

Banks-Blaney does plenty of that - but his polished boutique off Marylebone high street (just up the road from Selfridges, round the corner from an outpost of the boutique MatchesFashion.com) is remarkable because it's a destination for fashionable women themselves, not just the people who dress them. The striking thing about William Vintage's store is how un-vintage it all looks; it's sleek and modern (evidence of that interior design past), rather than crammed with bric-a-brac and slightly tumbling down, a look that has become sly visual doublespeak when retailing pre-aged garb, and one that probably allows unscrupulous sorts to flog clothes that, in all honesty, aren't that old. Banks-Blaney's example reverses the outcome: his clothes frequently don't look old, even when they're a mid-century Dior haute couture dress (very this season Céline), or a late eighties Thierry Mugler (totally winter Saint Laurent). "Pared-back, modern, clean," is Banks-Blaney's description. "A place where you can find precious things, but not displayed in a precious way. To show how wearable they are, and how relevant."

Amal Clooney at the premier of Hail, Caesar!, in a 1981 Yves Saint Laurent dress from William Vintage (Getty)

That's perhaps why William Vintage's clothing appeals to women who wouldn't be caught dead in something self-consciously dubbed 'vintage'. Women like Kristen Scott Thomas - who, like many actresses, spends a good amount of time in picture-perfect re creations of past eras, but nevertheless chose to wear a 1948 Balmain dress to last year's BAFTAs. Earlier in the year, at the launch of her film The Other Woman, Kate Upton had looked preened and polished in a mid-century creation by Ceil Chapman - little known but, reportedly, the favourite designer of Marilyn Monroe (fitting for Upton). And earlier this year, Amal Clooney wore a 1981 Yves Saint Laurent haute couture gown to the premiere of Hail, Caesar!. All were, obviously, courtesy of William Vintage, whose proprietor finds vintage treasures at auctions, estate sales, and sometimes by approaching families direct. Meeting one French dynasty, avid collectors of haute couture, resulted in the unearthing of a 1954 Balmain ballgown in pristine condition: it was preserved in a Parisian cellar, in a Tupperware box.

The vintage matters to Banks-Blaney - and perhaps, to some of his customers, such as Rachel Zoe, an avid enthusiast as well as friend and client who wrote the foreword to a book, 25 Dresses, that Banks-Blaney published last year. But for many, the question of provenance never comes up - rather the basics. Does it fit? Does it flatter? "My approach as a buyer, and our approach as a company, is to get those pieces where it doesn't matter if it's Saint Laurent for Dior from 1958, or a seamstress-made dress from the 1960s that doesn't have a label in so it's 200 pounds. It's not about value, it's not about designer, it's not about legacy-making. It's about a garment which has had a life before you've had it," states Banks-Blaney. "And I think there's an amazing magic to that."

Kate Upton at the premier of The Other Woman in 2014, in 1950s Cecil Chapman from William Vintage (Getty)

Banks-Blaney is staking a bet on that translating out of the flesh and across the Internet --this week, he launched a reconfigured William Vintage website, going live with around 800 pieces, a number set to rapidly climb to 2,000. He dubs it "the net-a-porter of vintage," which describes both the site's aesthetic and the range of product on offer. Like any high-end online retailer, you scroll through an array of several thousand designer dresses. The difference at William Vintage being that each is entirely unique - vintage haute couture mixing with what he dubs "Great Unknowns". There's a "resort" section of frilled and flounced mid-century bathing suits, for instance, that look remarkably contemporary. Which is the important thing about the site - it makes you look at vintage in a different way. Just like Banks-Blaney, there's no mothballs in site (or scent).

William Vintage has been online before - but, Banks-Blaney states, this is a different proposition entirely. "Our first website really came online to be a tiny representation of what we carried. We never had more than about eighty pieces on it. It was done for two reasons: firstly very quickly, we started to receive quite strong international interest... and it was also putting our foot into the water. When that website launched, we had two people. Including me. Three years down the line, we've grown a thousand per cent. We're a bigger team, and we've been buying aggressively," he pauses, names a figure spent at one auction, but asks me not to repeat it. Suffice to say, expect great things.

Style ambassador: Banks-Blaney marries his intimate knowledge of styles past with his love of contemporary fashion

"The manifestation of the shop and of the experience," is how he describes it - it's simple, slick and looks decidedly expensive. Zoe is in there - she's a guest curator, a section of the site Banks-Blaney is keen to open to celebrity supporters and industry experts. It's also, most importantly, filled with incredible clothes - vintage couture, unknowns and, he excitedly relates, the beaded Bob Mackie gown sported by Sharon Stone as Ginger Rothstein in Martin Scorsese's Casino.

Like any high fashion site, William Vintage will offer worldwide shipping and returns, packaged in custom boxes, wrapped in tissue. The whole works. But it's all being handled in house, a mammoth undertaking, but one Banks-Blaney feels passionately about. "We're not storing everything in warehouse, it's not dealt with by men in dungarees," he emphatically states. "Vintage is always a little bit more effort. You can't say 'Oh I'd love that dress, but I want it in red and I want it in a size six.' It's a process of discovery. The same for me as a buyer, and I want that for the end user. I want someone to visit our site and delight in the fact that they click purchase on this dress that's a complete one-off." Then, he smiles. "And if it doesn't fit you, no problem. We do free return shipping!"

WilliamVintage.com