IT'S BEEN A YEAR NOW since I opened Flashback, my vintage dress shop. Before that I had a stall on Portobello but that was hard going, especially in the winter, having to haul the clothes in and out of the van on freezing dark mornings then standing around in the cold all day. So when a friend told me about a lease that was coming up on this site in Hampstead, I took a deep breath, decided to go for it and, so far, it's been a success. People seem to enjoy coming here - perhaps because the interior's modern and light and the clothes are well displayed with plenty of space between the hangers. So many vintage dress shops are a mess, with bags and shoes all over the place and the rails so crammed that you give yourself an upper body workout just going through them. Flashback isn't a bit like that - it's more like being somewhere nice, like Phase Eight. Then of course there are the clothes - a necessarily eclectic range from the flapper dresses of the Twenties to the New Look suits of the Fifties right through to the spangly bat-winged tops of the early Eighties. My customers say that coming into Flashback is like entering Aladdin's cave.

People ask me what I like most about what I do, and, of course, a great part of it is the pleasure I get from working with garments that are so well made. These clothes haven't been churned out by the thousand in some faceless factory - they've been made with real craftsmanship, artistry and pride.

Take this midnight blue silk taffeta evening dress for example. It's by Balenciaga from about 1960. Look at the elegant simplicity of the cut, and the way the hem is slightly raised to reveal shoes. Look at the deep band of silver beading that encrusts the neck and hemline. Where would you find something of this quality today? Then there's this oyster pink backless evening gown, from the mid-1930s. I adore its heavy cowl neckline and its sweeping fishtail hem, not to mention the miraculous bias cutting which makes the satin drape like oil.

So yes, the superb quality of vintage clothing is a major part of this job's appeal. But for me there's something else. Something philosophical, almost. Please don't laugh, but what I love most about these amazing old clothes is the thought that they contain someone's personal history. I find myself wondering about the women who wore them. I find myself speculating about their lives. I can never look at a garment - like this early 1940s green tweed suit here for example - without thinking about the woman who owned it. How old was she when she bought it? Was she married? Was she pretty? Did she work? Did she have children? As it has a British label I find myself wondering what happened to her during the war and whether or not she survived it. Then I look at this pair of embroidered evening slippers here, and I imagine the woman who owned these dainty shoes rising out of them and walking along in them, or dancing in them, or standing on tip-toe to kiss someone. I look at this little pillbox hat on its stand, and I lift its veil as I'm doing now, and I try to imagine the face beneath it. Because the thing about vintage clothing is that you're not just buying fabric and thread - you're buying a piece of someone's past.

This is something I've always given a bit of thought to, not least because at times, when handling the clothes, and especially when trying a garment on myself, I've felt a sudden tiny shiver run the length of my spine as though my soul has in some way connected for a split second with the soul of its former wearer. I know it sounds crazy, but this has happened to me several times now; and it's even led me to wonder whether the spirit of a garment's former owner can in any way influence the life of its present one. No doubt you'll find this notion fanciful - the idea that a ghost can lurk in a suit or a dress; but something has recently happened to me - something shocking - which has made me believe that it can.

But before I tell you the story - and even thinking about it makes me feel faint - I need you to know how I source the clothes.

I mainly buy them at auction, especially at smaller provincial auctions where the prices are lower than in London; I also buy them from private sellers - either from people who bring things into the shop or who I visit at home. I also get clothes from specialist dealers who sell garments from a particular era. But whatever their origin I always try to find out at least a bit about their background, not just for its own interest, but because if there is a story then I like to tell it to whoever buys the garment so that its narrative thread, as it were, can go on.

For example, I sold an Ossie Clark “floating daisies” dress last week, and I knew that it had once belonged to Julie Christie because she had given it to a friend who had given it to her daughter who, 30 years later, sold it to me. The woman to whom I then sold it was thrilled to know this about the dress and said that it would very much add to the pleasure of wearing it.

But to return to my own story. Sorry, I just need a moment to collect myself. I've been feeling very shaky lately. All right . . .

I often buy things from an American dealer, Rick, who specialises in US clothing from the 1950s. He goes to and from the States buying and selling Rockabilly gear, what I call “Preppie Americana” menswear - sleeveless jumpers, Brooks Brothers blazers and sea island shirts. Rick also sells prom dresses, those wonderful jewel-coloured strapless evening dresses with satin bodices beneath which foam layers of stiffened tulle sparkling with sequins. These dresses are so ridiculously glamorous and frothy that I call them “cupcake” dresses. I hang them on the wall, like paintings, because I simply love looking at them - they make me feel happy. As you can see I have three of them over there - that candy pink one, the lime green one and the cornflower blue with the lace banding. There was a fourth dress which was the most glorious, intense yellow you could imagine. I sold it a fortnight ago. But what I've learned since has so upset me that I doubt I'll ever buy another prom dress again.

When Rick showed me these four dresses at his small warehouse in Camden I asked him, as I always do, whether he knew anything about their background. He told me that he'd bought them from a young woman in LA who said that they'd belonged to her great-aunt and that they'd just been in a trunk for fifty-five years. Rick added that this girl had behaved rather strangely, as though there was more to say about the dresses but that she hadn't wanted to tell him.

Anyway, I was sitting in the shop one quiet Wednesday lunch time three weeks ago when a couple walked in. I immediately thought how odd they looked together because the girl was about twenty-five while her boyfriend was a good fifteen years older, maybe more. She was very pretty and petite - no more than five-foot-two, with glossy shoulder-length dark hair, warm brown eyes and an olive complexion - but with a noticeably hesitant, unconfident demeanour. The man was big and broad-shouldered with hands like paws. While she looked through the clothes he sat on the white sofa, which he almost filled, thumbing his BlackBerry. The girl spent two or three minutes going through the evening wear rail, apparently finding nothing. Then she looked at the cupcakes and I saw a light come into her eyes.

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