School's new rule says girls must wear trousers

St Aidan's CE High School, in Harrogate, has unveiled a new uniform policy for the next academic year which will ban female pupils up to the age of 15 from wearing skirts altogether.

Girls in Year 11 will be allowed to wear dark navy skirts so long as they are no more than three inches above the knee.

The changes have been brought in after concerns skirts were becoming too short as fashionable pupils responded to peer pressure and copied one another.

Parents who have voiced concern at the new policy have been invited into school to see for themselves.

A statement setting out the new policy on the school's website says: "Very young children, and even more disturbingly, special needs children are clearly wholly unaware of the signals they are giving out.

"Parents who have come in have been astonished to see the difference between the length their daughter may wear her skirt as she leaves home and what has happened by the time she is walking the corridors of the school."

The St Aidan's statement adds: "It does not need much imagination to understand where and in what situation the children are placing themselves 'at risk'. The first duty of care on any school is to keep the children safe."

The school says wearing short skirts is now an issue for a majority of girls at St Aidan's rather than a minority as pupils are copying one another. It also says most parents support the school's new trousers only uniform.

The rule will apply to all girls in years seven, eight, nine and 10 who will be required to wear black trousers – with jeans, cords or cotton drill material not accepted.

St Aidan's has also pre-empted the risks of midriffs being on display with "hipsters" and insists trousers must be similar in style to those issued by official school suppliers and low-cut ones will not be permitted.

The statement said: "We could, no doubt, on a weekly basis run detentions, exclude persistent offenders and thereby destroy the general 'bonhomie' within the school.

"The world has moved on. It is bizarre in 2010 to see wearing trousers as 'some form of punishment'. It is merely a change of uniform."

St Aidan's is a co-educational school with almost 2,000 pupils and is regularly one of the strongest performing comprehensives in the country at GCSE.