Author Andrew Tucker, a 28-year-old journalist with hefty experience garnered from working for trade publication Draper's Record, has managed to interview just about every designer currently working or showing in London from the notorious to the barely-acknowledged. In addition, the book provides an exploration of the city's better-known fashion districts such as Notting Hill and Knightsbridge and a directory of shops and markets in London.

For all his enthusiasm on the subject, Tucker is understandably wary about such tired tags as "Cool Britannia". "Although the hype surrounding London at the moment will go," he comments, "the creativity existing here will continue to flourish." The city's current - and enviable - reputation as a centre of design excellence began to emerge in the early 1990s but was quite clearly built on a long and tough preceding period. Tucker believes recession, perversely, is beneficial for fashion, obliging its practitioners to be more imaginative than might otherwise be the case. Many designers who now garner headlines and are perceived to be at the forefront of fashion "struggled for a long time. There are no overnight successes in British fashion." Traditionally, London has seen young names come to prominence and then, with rare exception, disappear as rapidly as they appeared. Tucker remarks of labels such as Scott Crolla and Body Map - which enjoyed high profiles during the 1980s - that "they are now fluff in the navel of fashion".

However, he believes this unhappy cycle may finally be broken for good. Rising stars such as Matthew Williamson, for example, are "very careful. Williamson has opened just a few accounts and is letting his business grow slowly and organically rather than believing his own hype. There's not the naivete there was in the 1980s. People are now much more wary and business-minded than they used to be." In addition, during the past few years a small number of designers who started in London have achieved international fame greater than any of their predecessors.

Tucker points to the astonishing ascent of Alexander McQueen. "He has set a precedent. He has risen from being on the dole - he used to sleep under the cutting table in his studio - to being the head of Givenchy. The optimism he has generated is just as important as his talent. His story is one that inspires other designers."

And, of course, the handful of stars is far from being the totality of London fashion. "British designers you see hyped on the catwalk are only a tiny part of the industry. Graduates from our design schools are working in studios all around the world - if you look at Versace, half the design team is British. They're never going to receive accolades someone in London can get but what they're doing is just as important."

Tucker admits there can be no simple explanation for why London should be so consistently rich in design talent but proposes a number of possible theories. "The thing about London is that there are so many different cliches, but it is a very difficult city to define. Paris has a very distinctive character and does fashion in a particular way; it's like an international airport lounge to which everyone comes and goes. Milan and New York are much more about business and marketing, about selling the product. London, on the other hand, is just so eclectic. There's a real encouragement that exists, a real have-a-go mentality."

London is a city in which novelty will always find a welcome and many designers barely out of college launch themselves on the market. "The downside of this is that a lot of people have conviction behind their ideas but are virtually broke. Someone like Vivienne Westwood is a prime example of that; only now is she starting to make some money."

Another reason for London's seemingly endless wealth of fresh design talent arises from England's long-standing fondness for eccentricity. "We like eccentrics here, we nurture people like that rather than treat them as outsiders." Furthermore, "things exist in London because people want to do something and find it exciting, not because they want to be perceived as fashionable.

Here everything happens almost by serendipity. And apart from clothes designers, London has an amazing crop of jewellers, milliners and textile designers. The context is extremely rich."

The London Fashion Book by Andrew Tucker is published by Thames & Hudson at £18.95 in the UK.