Study pictures of the latest red carpet looks and you'll find the best- dressed stars are increasingly those draped in vintage. They're among a growing band asking their personal stylists to source 'something old' - something that no other celebrity will be snapped in - rather than the latest designer offerings.

Recently, we have seen Michelle Williams (flapper-style dress at Cannes), Gwyneth Paltrow (Yves Saint Laurent in New York) and Renee Zellweger (emerald Christian Dior at the Golden Globes) in vintage, and they all looked fabulous.

It's not just the unique nature of these styles that makes vintage so sought after. In these greener times, there's something appealing about chic recycling. But such individuality comes at a price: trendy vintage boutiques such as Rellik in London's Notting Hill (a favourite of Kate Moss and Kylie Minogue) and Didier Ludot in Paris have seen prices of vintage clothing go through the roof.

Fortunately, many celebrity stylists know where to source fabulous vintage pieces for their star clients at knock- down prices.

Along with a handful of those in the know, they are privy to one of the fashion world's last remaining secrets. Every five or six weeks, luminaries of the fashion world head to a council building in West London to shop with a vengeance.

Behind the unpromising exterior of Hammersmith Town Hall lies a treasure trove of one- off fashion pieces. London Vintage Fashion, Textiles and Accessories Fair, held nine times a year and always on a Sunday, is packed with fashion industry insiders from as far afield as Paris, Milan and New York.

Bleary-eyed and incognito - at an hour when most people are still tucked up in bed - you will find them casting an expert eye over the wares of up to 100 antique clothing and accessory dealers from across the UK.

Here, for an entrance fee of £5, you can pick up this summer's key Seventies clutch bag in real python skin for just £48, or a pair of gold pointy-toe court shoes - tres Pierre Hardy and tres on trend - for just £45.

And how about this season's must-have maxi dress for less than £50 - cheaper than Topshop and with the added bonus that you're unlikely to bump into anyone else wearing it at this summer's festivals?

The items span an era from the 1800s to the 1980s. Yet many of the pieces slot perfectly into current fashion trends at a fraction of the price you would have to pay for the contemporary designer equivalent. While designer brands charge up to £40,000 for an alligator handbag, here you can expect to pick up crocodile, alligator or lizard skin ones for less than £100.

Not surprisingly, the fair attracts top fashion stylists searching for stand- out red-carpet outfits and fashion editors looking for fabulous one-off pieces.

But also skulking around the stalls, dressed down and desperately trying not to be noticed, are well-known designers hoping to find ideas for their next collection and even entire design teams from High Street stores, buying items for inspiration.

Burberry, Jaeger, Stella McCartney, Topshop and Miss Selfridge have all been spotted here, while Donna Karan is said to have spent £60,000 on clothing and vintage textiles on one stand, skilfully beating down the dealer who didn't recognise her.

Jean Paul Gaultier slipped quietly in and out of the last one almost unnoticed, while John Galliano arrived at a recent fair with his entourage at 8am.

Italian designer Alberta Ferretti, handbag designer Lulu Guinness, retro print guru Cath Kidston and shoe designer Emma Hope are also on the roll call of fashion glitterati who frequent the fair.

'It's like a fashion family outing,' says one stallholder, who prefers to remain anonymous. 'Absolutely everyone comes - all the designers, all the design studios.'

'You have to be very, very careful,' says another dealer. 'Discretion is everything. Designers mustn't know what another designer has bought.

'It's the same with the High Street stores who don't want the competition to know what they're about to pull apart and reproduce, while pretending to have created it themselves. But you can always spot a professional buyer by the way they rifle through the rails.'

Karen Wheeler picks up a bargain at the London Vintage Clothing Fair in Chelsea

While vintage designer labels such as original Sixties Pucci, Seventies YSL and Ossie Clark are always in demand, littleknown labels are worth seeking out, too, according to fashion writer Edwina Ings-Chambers.

'It's not necessarily the big label stuff. It's what many people would call second-hand. But if you have a good eye and know what's fashionable, you can pick up items that reference the season's key trends at very reasonable prices,' she explains.

But the Hammersmith vintage fair is not just a mecca for members of the fashion industry. It also attracts members of the public, lured by the promise of highly individual pieces, some at the sort of prices you find in Primark.

'The price of vintage clothing has soared in recent years and it's almost impossible to find bargains in flea markets or Oxfam any more because the boutique owners will have got there first, selling them on, often at huge mark-ups,' says antique clothing expert Matthew Adams. 'By buying directly from a dealer at a fair, you are cutting out the middle man.'

The Hammersmith Fair is organised by former antique clothing dealer Paola Francia-Gardiner, an enthusiastic Italian.

'By the early Nineties, the vintage market was almost dead,' she says. 'No one was buying the clothes because fashion had moved on. Other dealers were complaining that they had a lot of stock that they didn't know what to do with, so in 1999 I decided to organise a fair incorporating not just vintage clothes but accessories and textiles.'

Since then, she has seen the profile of the vintage shopper change considerably.

'To begin with, it was a small clique of fashion designers, collectors and perhaps film and theatre costumiers,' she says.

'In the past few years, though, members of the public have started coming in increasing numbers, inspired by highprofile celebrities who wear vintage. Julia Roberts was very influential when she wore vintage Valentino to the Oscars.'

Two other events eagerly awaited by fashionistas - who travel from all over the country to attend - are Frock Me!, held six times a year at Chelsea Town Hall in West London, and Anita's Vintage Fashion Fair, held bi-monthly at Battersea Arts Centre in South London.

'Most people who work in fashion know about these fairs,' says Yasmin Yusuf, creative director of Miss Selfridge. 'They're a really good source of one-off pieces and some of the dealers selling the clothes are real characters. My tip is to check out their websites for the start times and arrive early.'

Treasures to be found at the London Vintage Clothing Fair in Chelsea include this snakeskin clutch bag and gold court shoes

She and her team had done exactly that on the Sunday I attended, scooping up many pieces which not only provide ideas for new collections, but are subsequently sold under the label Miss Selfridge Vintage - a collection of vintage oneoffs offered on the website missselfridge.com.

A new collection goes up every month: currently it is Fifties prom dresses (ideal for summer weddings) in pastel pinks, blues and lemons, £90 to £120, to be followed by Lingerie Vintage.

Next stop for Yusuf is Frock Me! a couple of miles away in Chelsea, where the ladies toilets have been turned into a makeshift changing room, with women of all ages wiggling into Twenties' chiffon tea dresses and Fifties' prom dresses. There is even a vintage pre-war-style tea room, with vintage china, staff in vintage black and white uniforms, potted palms and a gramophone playing in the background.

Kylie Minogue, who just happened to be walking down the King's Road, popped into a recent Frock Me! with her parents and bought a white voile dress from the Twenties. 'But no one took any notice of Kylie,' says one stallholder.

Celebrities and fashion royalty are nothing out of the ordinary here. Similarly, no one turned a hair when Yoko Ono pitched up at the last Frock Me!, trailed by an entourage, who paid for her purchases as she swanned from stand to stand.

'Because no one makes a big deal of it - and because it is a paparazzi-free zone - celebrities can shop in more privacy than they would on Bond Street,' says Frock Me! founder Matthew Adams.

But, increasingly, rubbing shoulders with the stars and designers are fashion fans who love the idea that they're buying the sort of pieces that might be inspiring next year's catwalk collections.

As one shopper says: 'It is really exciting to shop in the same place that inspires so many bigname designers. There is something very thrilling about the idea that you're stealing a march on fashion royalty.'

There is no doubt that these fairs are a hotbed of ideas for designers. And who knows? Maybe that Sixties dress or the detailing on a Twenties blouse you bought will inspire the next Gaultier collection. Or you might even see it reinterpreted in a year's time on the catwalk by John Galliano, Donna Karan or Stella McCartney.
The next London Vintage Fashion, Textiles & Accessories Fair is at Hammersmith Town Hall on Sunday, June 15, from 10am to 5pm. Admission £5. In addition, there is an Antique Textiles, Costumes and Tribal Art Fair on June 8 (020 8543 5075, www.pa-antiques.co.uk).
Frock! is at Chelsea Town Hall, King's Road, London SW3, next Sunday, 11am-5.30pm. Admission £4 (020 7254 4054, www.frockmevintagefashion .com).
Anita's Vintage Fashion Fair is at Battersea Arts Centre, Lavender Hill, London SW11, on Sunday, July 13, 9.30am to 4.30pm. (020 8325 5789, www.vintagefashionfairs.com).

DOs AND DON'Ts OF BUYING VINTAGE
DO your homework and plump forwearable pieces that reflect the season's catwalk trends. This summer it's all about floral Thirties tea dresses.
DO pick a design classic. Investment pieces such as Fifties prom dresses will never go out of fashion.
DO invest in accessories. It's a great way to ease yourself into the vintage trend without committing to an entire 'retro' outfit.
DON'T skimp on quality. Beautiful silks, suiting and wool will all wear better than cheap, man-made fabrics.
DON'T be led by the label. Remember, old sizes run much smaller than their modern-day equivalents, so be sure to try everything on before you buy.