Two decades of fashion collide inside Dredd Experience, a tiny shop in the West End of London. An Ossie Clark black crepe nightgown fit for a vampire queen hangs next to some neatly pressed denim safari suits from the Seventies; matching hippie smocks and flares in wildly embroidered chiffon nuzzle up against a rack of Sixties slimfit button-down shirts.

'Clothes are so romantic, dude, I love them,' gushes Jennie Mathias, the shop's energetic proprietor. Zipped into a fluffball of fake fur, with thick dreadlocks peeping from under a dippy patchwork hat, she gestures enthusiastically around a shop stuffed with relics of yesterday's youth culture. 'Clothes are collector's items,' she says. 'It's the same as records.'

A few streets away from Dredd Experience is another shop, Acupuncture, selling vintage punk and Vivienne Westwood originals for prices that rise well into the hundreds. Mathias's prices are more modest, with Fiorucci 'Love Boots' (lurid designer wellies which have to be seen to be believed) selling for less than pounds 30.

Twelve years ago, Jennie Mathias was better known as Jennie Belle Star, lead singer of the Belle Stars, an all-girl, seven-piece pop group. They had a big hit with the anthemic 'Sign of The Times', and toured Europe with The Clash; Jennie Belle Star was a fully-fledged pop star. Why did it end?

She gives me the sort of look that says she could have done without the question. 'We were all sick of each other. Three Virgos and four Leos in one band? You know what I mean?'

And how did she end up running a fashion shop? 'What else could I do?' she retorts. 'I couldn't think of anything else. I'm only into music and fashion, I know nothing about anything else.'

After the Belle Stars, she spent 10 years organising fashion shows in the Miami nightclub owned by Ron Wood of the Rolling Stones, performing at European jazz festivals and finally finding herself just an ex-pop star. 'I spent a couple of years living in London squats wanting to be a hobo. I just dossed around and couldn't really decide what I wanted to do.

'I hadn't grown up really; I was still looking for something good to do. I tried to hold down a couple of ordinary jobs but it wasn't really me.'

Her story is interrupted, first by an immaculate scooter boy who slides off his Lambretta and comes in to ask about suede bowling shoes and Fred Perry shirts, then by a small-time clothes dealer with a bag full of what Mathias calls 'deadstock': pristine items that have spent the past 20 years in a warehouse. She is hungry for this 'good- as-new' vintage wear, and has already found Seventies police jackets and Eighties silk shirts in fragile, stained-glass colours.

The good-as-new relics aside, the most popular stock in Dredd Experience is a range of new jackets and coats co-produced by Matthias and her sidekick Terry Rawlings. The label is called Harry Palmer, in honour of the working- class spy played by Michael Caine in the film The Ipcress File, and reflects that character's cool, sharply tailored mod style.

The range has been endorsed by the singer and mod icon Paul Weller, who offered the designers tips on early Sixties style details. A standout Harry Palmer item is a three-quarter-length coat in green suede with shiny black leather trimming and a silk lining.

'It's very sharp stuff - spot on,' says Tony Jackson, whose company, Global Village, has just finished shooting a promotional film for the range. You might call it Reservoir Mods - clean-cut Vespa-riding boys in shiny Palmer coats wielding sub-machine-guns.

'A lot of people dress down these days,' says Jackson, 'but Harry Palmer represents the England of yore and the heroes we're sort of attached to: sharp-suited Englishmen drinking double Scotches and toting machine-guns.'

Mathias is also drawn to the dandified 'mod' styles. Forget the tabloid image of mods as bank holiday rioters and amphetamine addicts (the name 'mod' is derived from the stylistically distinctive young followers of modern jazz); for her they were ice-cool super-narcissists striving for immaculate street fashion.

'But this isn't just a shop for classic mods,' she says. 'I'm branching out to reach the psychedelic phase of the Sixties and chase it through to the looks of Marc Bolan, Eno, Bowie and the early Seventies.'

What is the right tag for this diverse gathering of mod, hippie and glam styles? We exchange a few suggestions, such as my 'Nineties Beatnik' - and she reaches for a notebook and a pen and starts jotting down some things I have said.

I am the one who is doing the interview: what is she up to?

'I write poetry - it's the only way I can relax,' she explains. 'I say goodnight to my mum, go to my bedroom and sit writing before I go to sleep. I pick up on stuff that happens during the day.'

She adds: 'I don't treat conversation lightly. I use it to my best advantage.'

Dredd Experience, 20 Hanway Street, London W1 (071-636 6502).

(Photograph omitted)