Image caption The first three pictures are from Stella McCartney's 1995 graduation show (Rex Features). The last three are from her latest autumn/winter collection (Getty Images)

A large number of the designers showing at London Fashion Week have passed through Central Saint Martins. But why does this school dominate?

Even if you're not hugely into fashion, chances are you'll have heard of Stella McCartney, John Galliano and the late Alexander McQueen.

They're fashion superstars, celebrities of haute couture, newsworthy personalities in their own right, as Galliano's recent trial for racial slurs showed. But what also unites them is their alma mater, as all three studied at Central Saint Martins College of Art and Design.

To name drop a bit more, its fashion alumni also include Katherine Hamnett, Bruce Oldfield, Jenny Packham, Matthew Williamson and Christopher Kane.

But it has not just spawned great British designers. Riccardo Tisci, the Italian creative director of Givenchy womenswear and among those tipped to take over from Galliano at Dior, went there.

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Others include American Zac Posen, worn by Natalie Portman and Beyonce among others, and Greek-born Mary Katrantzou, whose print dress adorned Keira Knightley at this year's Venice Film Festival.

Only the fashionistas will have heard of Kane and Katrantzou, and only the hardcore will have heard of the Central Saint Martins designers who don't have their own label but who help power the world's biggest fashion houses, such as Chanel, Gucci and Louis Vuitton.

CSM, as it is known to staff and students, has been around a long time but its reputation as one of the world's top fashion schools was forged in the 1980s. Its fees are in line with other fashion schools but it is notoriously hard to get a place, with the MA in fashion receiving 600 applications for 50 places.

The Daily Telegraph's fashion correspondent Hilary Alexander says the school nurtures the free-thinkers, the mavericks, the people who think outside the box.

Image caption Alexander McQueen's work: His 1992 graduate collection, pictured first, was bought by the late fashion icon Isabella Blow (Copyright: CSM and Getty)

"The training is very anti-establishment. But that is underpinned by a knowledge of pattern cutting and how clothes hang. It's not an anarchic free-for-all, there's a rigour in terms of the disciplines that go towards making a designer."

It would be impossible to put a monetary value on the school's contribution to global fashion, she adds.

"It must be millions and millions when you think of the influence, inspiration and sales of people like McQueen, Galliano, Williamson, McCartney... the list goes on and on and on."

Central Saint Martins It formed in 1989 from the merger of the Central School of Arts and Crafts (founded 1896) and St Martin's School of Art (founded 1854)

St Martin's was internationally renowned for fashion and fine art, while Central was well-known for theatre, industrial and graphic design

Its non fashion-designer alumni include artists Lucien Freud and Antony Gormley, designers Sir James Dyson and Sir Terence Conran, actors John Hurt and Colin Firth, and singers PJ Harvey and Jarvis Cocker

In 1999, Drama Centre London (founded 1962) merged with CSM

CSM is part of the University of the Arts London, which brings together six colleges across the capital

It was spread across 11 buildings on six sites but it's moving to a new base at King's Cross and an existing site in Archway this year

Its fees are set by the University of the Arts London. From next year, an undergraduate course will cost £9,000 per year

It is undeniable that Saint Martins has produced more than its fair share of big name individuals.

Out of the 86 brands showing during London Fashion Week (LFW), 41 involve CSM designers. It is also the only college deemed professional enough to have its own show at LFW.

Savannah Miller is one of the many CSM graduates preparing for this year's LFW, which kicks off on Friday 16 September. She runs her Twenty8Twelve label with her actor sister Sienna Miller.

The fashion designer Miller, who specialised in knitwear and graduated in 2004, says it has a very hands-off approach to its teaching.

"They leave you to get on with it and that made you so free. There were people who couldn't handle that kind of freedom - they wanted classes and structure but you only saw a tutor once every two weeks.

"I was in from 8.30 in the morning to 8.30 at night. There was a handful of us doing that and it was those people who have gone on to do well. "

And if she wasn't studying, she was working at the McQueen label.

"We didn't have any free time to hang out in the pub. We did have fun but fashion is a competitive environment and you had to put in the work."

Of course, one might argue that the school benefits from a virtuous circle. It produces the top designers so it garners the attention that helps it produce top designers.

Image caption John Galliano's work: His French Revolution-inspired 1984 graduation collection was bought by London boutique Browns (Copyright: CSM and Getty)

Its reputation enables Saint Martins to attract the best tutors and talent, as well as interest and investment from the industry. Its alumni feed back into the college, with former students returning to give talks and offering work experience.

Its professional reputation also means global brands, such as Puma, are keen to sponsor projects providing both industry experience for the students and revenue for the college.

Fashion consultant Andrew Tucker says there are plenty of other fashion schools in the UK, such as the faculties at the University of Brighton and Newcastle University, the Royal College of Art (RCA) and London College of Fashion.

Image caption Savannah Miller (left) launched a fashion label with her sister Sienna

He says each has its strengths and there is no resentment about Saint Martins having the highest profile.

"Central Saint Martins is genuinely brilliant and I think that's particularly down to the course directorship of Louise Wilson. It's a bit like Fame and someone like Louise is almost a celebrity in her own right. You get people who just want to go there and nowhere else.

"It is the place for someone who is very individual, who wants to be a fashion designer, who has their own message."

Head of MA fashion Prof Wilson is adamant that her job is not to produce labels but to teach her students the skills they need to succeed wherever they choose to pursue a career in the fashion and wider creative industry.

"British Fashion Week is the bane of my life. I've got far more students all round the world in high positions of the fashion industry which is far more satisfactory."

Former CSM student Bruce Oldfield's client list includes everyone from the late Diana, Princess of Wales and Queen Rania of Jordan to Jemima Khan and Rihanna.

He contemplated going to Kingston, Saint Martins or the RCA as they were the "most hi-vis colleges where you would be noticed if you had something to say".

Image caption Stella McCartney's graduation show included a few of celebrity friends

Oldfield says he wasn't very sociable, kept his head down and grabbed all the opportunities Saint Martins offered. He found the atmosphere and language a "bit precious".

"I floundered on some of the over-intellectualised projects that I do recall. I just got on with designing what I wanted to do and they seemed happy enough with me."

Jenny Packham's dresses are worn by Hollywood A-listers and royalty - the Duchess of Cambridge has worn three of her creations this summer - and she says it was "survival of the fittest" at CSM.

She describes the teaching style as "passive aggressive" and says the tutors are all "without exception committed and enthralled by their subject".

"One day in one of our history of fashion lectures I sat in the front row. I turned round to find that out of a class of 30-ish I was the only one awake. The lecturer was so passionate about his subject that he had just continued."

CSM is currently in the throes of moving to a new base in King's Cross. Many of its old fashion graduates have been lamenting the loss of its Charing Cross Road building, which was deep in the heart of fashionable Soho but a complete dump internally, by all accounts.

Despite the buildings decrepitude, the crumbling corridors fostered an array of talent.