Schoolgirls' hemlines are on the rise, according to a new study. The average skirt is now six inches above the knee – that's a rise of three inches in the past five years.
The study, conducted by the laundry company Dr Beckmann, also found that most parents are not laying down the law about skirt length.
Two thirds of mothers say they do not argue about hemlines, even though most (81 per cent) argued with their own mothers about school uniforms when they attended school.
"The popular school mini-skirt is fast becoming the school micro-skirt," said Susan Fermor, a spokesman for Dr Beckmann, which conducted the research.
"School uniform tends to follow fashion to a degree but seems much slower to catch up than other forms of clothes. But short school skirts never seem to go out of style.
"Schoolgirls don't seem to the rules stop them - they just hitch up their waistband once they leave home in the morning. Their mums are wise to it though - they realise their daughters' skirts are getting shorter.'"
Teachers fear that Education Secretary Michael Gove's plans to let parents buy school uniform basics in any shop means that hemlines could rise higher.
Louise Robinson, the headmistress at Merchant Taylors Girls' School, Crosby, told The Times: "Girls are only reflecting what is now the social norm. People are dressing more casually for business and it has filtered down into schools."
She fears that new rules on uniforms will make hemlines hard to police. However, she fears that schools will struggle even more to impose reasonable limits on their pupils when new rules on school uniforms are introduced.
"The first thing a school can do to keep a grip on skirt length is insist on a specific skirt, so what Michael Gove is suggesting is going to leave us even more exposed to fashion," she said.
Mr Gove has said that schools must stop using particular suppliers for their uniforms.
New guidance will also state that schools should keep compulsory branded items to a minimum, so that parents can shop around for the basics at ordinary clothes retailers.
"If pupils can buy a piece of uniform anywhere, they can say that they could not find a knee-length skirt in Topshop or Zara. It will make things much more difficult," said Ms Robinson.