Shock as designers go smaller than size zero

Fashion designers have revealed their latest marketing innovation for the world's skinny women - a size smaller than zero.

This summer British clothes stores began stocking the waif size 4, following the rise of the equivalent size in the US: size 0. Now America is once again leading the way with a new size - 00 - for waists the circumference of a child's football.

Banana Republic, which is owned by Gap, is already advertising 00 clothes on its website. Another company, Nicole Miller, is planning to introduce "sub-zero". It said customers were complaining they had to take in the existing size 0 clothes. Alison Hodge, a spokeswoman for Nicole Miller, explained: "We've introduced this new size for naturally petite women, not for models who have dieted themselves down to a dangerously low height to weight ratio."

But dieticians and commentators feared the new size - a size 2 in the UK - would increase pressure on the 1.1 million Britons with eating disorders. Dr Dee Dawson, clinical director of the Rhodes Farm Clinic in north London, which treats adolescents with anorexia nervosa, said: "It's absolutely ridiculous. No woman can possibly wear those kind of clothes and be healthy. You have to be in a state of starvation." She added the young women in her care were "more interested in the size on the labels than the style of the clothes".

The very slender builds of catwalk models has been a subject of debate this year after the publication of pictures of Victoria Beckham wearing jeans reportedly fit for a seven-year-old.

Last month Madrid City Council banned from its fashion week models with a body mass index (BMI) of less than 18 - a ruling that would disqualify Kate Moss, who, according to insiders, has a BMI as low as 15.

This week there was speculation over the weight of Marianne Berglund, a contestant in Channel 5's Make Me A Supermodel reality television show, who was pictured with her ribs and hip bones sticking out in a swimsuit. In August an emaciated 22-year-old model, Luisel Ramos, died of a heart attack moments after stepping off a catwalk.

Although British women have increased in size since the 1950s and Marks & Spencer's most popular size is 14, Miss Selfridge and Topshop both stock size 4. A spokeswoman for Topshop said there was "no consumer demand for a smaller size".

Images of thin models "influenced the thinking" of people vulnerable to eating disorders, warned the Eating Disorders Association. People with anorexia had been found to keep scrapbooks of skinny models, said spokesman Steve Bloomfield. But he defended the right of clothes companies to sell whatever size they wanted.

Dieticians are concerned by the development. "If people are going on extreme diets and starving themselves - to attain some of these extremely small sizes - it can put them at risk of serious dietary deficiencies and long term health problems," said Dr Frankie Phillips, of the British Dietetic Association. By offering these sizes it's definitely putting pressure on people to be slim or even slimmer."

The former Cosmopolitan editor, Marcelle D'Argy Smith, who has been campaigning against the extreme thinness promulgated by the fashion industry, said: "I'm sick of it. I loathe it," adding: By sticking an extra 0 on, designers are seen to be fashionable. They might not make much more money but it makes them look as if they've got the concept, got where it's at."