It's fairly unlikely that when a Victorian lady was laced into her frilly underwear of a morning, or a wannabe 1930s starlet dipped herself into a bias-cut piece of silk, or a fashion-conscious 1970s hippy chick snapped up a groovily printed number from Biba for just a few pounds, that any of them might have paused to consider that, one day, their wardrobe staples might become collectibles.

Understandably so. Who would imagine that her undies or high-street purchases would one day be worn - even fought over - by the fashion elite? After all, it's jewellery that has long been considered to be the wearable heirloom, with the family jewels, however humble, being passed down from mother to daughter. Old clothes were just something for the charity shop.

But, with the rise of vintage, that's no longer the case. And though few of us today might take into account the possible goldmine that may lie in our wardrobe purchases, when out shopping it is wise occasionally to keep an eye on the long-term future of our clothes. Consider that a Biba dress that once cost about £3 might now change hands for around £800 and you'll begin to see the logic. So which contemporary designers might just land you or a loved one in the money in years to come? We put the question to a few fashion insiders to see who'd get the nod of future approval.

For the most part the answers are not surprising. Lanvin, under current creative director Alber Elbaz, and a favourite label with fashion editors, wins pretty much hands down. "It's so individual; it has such a specific handwriting that won't date, and that handwriting is in the details and in the quality of the fabrics," says Ivan Donovan, women's wear buyer at Browns. "Lanvin is not trend following, it's trend making." Lanvin has even made it easy for owner to catalogue the designs: each label comes with the season and the date embroidered on it, so no future arguments about provenance.

Virginia Bates, who runs the famous Virginia vintage clothing shop in London and specialises in Victoriana, also doesn't hesitate in naming Elbaz at Lanvin as a future desirable, but names John Galliano, Alexander McQueen, Philip Treacy, Stephen Jones and Manolo Blahnik as other labels she'd keep for the future.

"I think they are all so original: their workmanship is super, the designs are fantastic - they're just glorious," enthuses Bates. "And Manolo was the first to do anything that was a bit different with shoes."

But for Bates, the quality of the workmanship in a garment is just as key as the quality of the design. "Quite apart from anything else it will last if it's made well, and that's what's so wonderful about the antique pieces - they were hand-made and finished properly, whereas a lot of the modern stuff I frankly don't think is."

But aside from the usual suspects, how can you determine whether what you're buying now might one day be seen as important?

Partly the answer lies in the designer's ability to be forward-thinking.

"I think designers such as Junya Watanabe and Comme des Garçons will be

collectable. You do see references or influences in their designs, but they're so their own that they are completely modern," says Donovan.

"I see Comme pieces, for instance, that people have owned for five, 10 even 15 years, and they still look fresh and just as new and just as unique."

Cameron Silver, owner of Decades in Los Angeles, and arguably the world's king of vintage clothing, sums up what he sees as the collectable fundamentals: "I think designers who are directional are not overly derivative of the past and, ultimately, become editorial favourites, are a very good indication of future collectables," he says. Again, Silver references Lanvin. "What Alber has done has been so influential - he's the king of the frayed edges - and it represents a very distinctive moment in contemporary fashion. And everything Rei Kawakubo [at Comme des Garçons] does has the potential to be collectable, as she beats her own drum." Silver also includes McQueen and Galliano on his hotlist - though has reservations about how much we'll be clamouring over pieces that carry a Dior logo in 50 years' time.

So what of seminal designer collections; say Tom Ford's finale at Gucci? The first collection of a designer and the last collection of a designer are likely to become sought after, says

Silver. Likewise, short runs such as Galliano at Givenchy - and even McQueen at Givenchy - will probably prove popular. "That's the weird thing that can happen with vintage: we can rediscover designers' collections that weren't so appreciated at the time. So maybe we'll look back at Alber at Yves Saint Laurent or Alessandra Facchinetti's last collection at Gucci and feel they were complete geniuses."

But largely such "genius" designers must have somehow captured a fashion zeitgeist - so hold on to your Tom Ford at Gucci and YSL - rather than simply be a well-known name. Silver and the others, for example, don't imagine Jil Sander's final collection for her house is likely to become collectable. "Sander's not directional, though you could say that she does what she does better than anyone else," says

Silver. He also notes that early Armani is more collectable than later Armani; ditto Helmut Lang. He also suggests that Prada is always directional, that Rocha's clothes are beautiful, and "anything Alaia does is great, you can't go wrong with having some Alaia".

Where others think high-street clothing may have no future relevance, Silver is not so sure. "I'm sure the Karl Lagerfeld range for H&M will prove a collectible - Lagerfeld is not just a great fashion designer but a great businessman, and his work is a visual example of a text-book academic lesson on fashion and business." And Silver even believes there may be a place for last summer's jelly bag in some collections. "If you wanted to do a retrospective of that season you'd definitely have the jelly bag," he reasons.

Which brings up the point of museums in general. Presumably, when a designer reaches the level of a retrospective, they enter the realms of

being collectable, which would make Viktor & Rolf, Versace, Vivienne Westwood, Hussein Chalayan and Yohji Yamamoto sure-fire winners. Oriole Cullen, co-curator of the "London Look" exhibition currently at the Museum of London, thinks it's certain to help, just as an item that is part of a museum collection will probably be more desirable.

Though the Museum of London must concentrate on items that resonate with Londoners, Cullen believes that for general collectors, "it will only be the recognisable pieces that people will ooh and ah over. So, if something was worn by a celebrity, was featured on a Vogue cover [such as the museum's recent purchase of a Jonathan Saunders dress from the British Vogue January 2004 cover], then it will have an impact. And it usually turns out that it's the best-seller or limited editons that are more desirable."

But at the end of the day, apart from the almost guaranteed hits, as Cullen points out, "it's very hard to pinpoint what will be a future classic". Ultimately, the best advice is that if you love it, look after it, and never, NEVER, cut out a label. In this business, provenance is everything.

PRESERVING THE GLORIES OF THE PAST THROUGH INSPIRED MODERN COLLECTIONS

Not content to rely on dealing with antiques, Kyra Segal, co-owner of the Gallery of Costume & Textiles in London, a veritable trove of special pieces, decided to make her own range of clothes that paid homage to the best that's gone before. 'Over the last few years I've seen that the sources of the really beautiful vintage pieces have been dwindling and I wanted to try to keep them in existence,' says Segal.

So she kept to one side special items that she could use to create patterns and as examples of traditional workmanship, and set about designing new pieces and sourcing expertise worldwide: pieces are cut in London, a small UK factory does sampling and makes the wedding dresses, while the embroidery and smocking is done in Vietnam.

For Segal, this has been a labour of love. It took her 18 months just to perfect the cut of her coat: a motoring coat- inspired mix of Mary Poppins Victoriana with a dash of Marni-esque modernism. Yet, in intricately smocked tunic tops in Irish linen, 1930s-inspired bias-cut jersey dresses, and bead-encrusted silk tops, Segal has not only taken inspiration from the past, but created inspirational pieces for the present. And her work can be worn by anyone, from a Kate Moss customer to a gardening grandmother - it just depends on the accessories.

Karina Duebner founded Tamerlane's Daughters for similar reasons. A collector of 19th century central Asian textiles and jewellery, she decided she would like to 'use them in the way they were intended - to be worn by women. I wanted to breathe new life into them as opposed to their being hung on a wall.'

Duebner used dressmaking skills acquired during her East German childhood ('if you wanted to wear something nice you had to make it yourself') to create her bespoke range of garments that incorporates old swatches of material or jewellery. So a gown may have a strip of antique embroidery across the bust, or a halter- neck dress will flow from a necklace, creating a modern way to look to the past.

Edwina Ings-Chambers is the FT's deputy fashion editor