Girls are being banned from wearing skirts in school amid concerns their ever-rising hemlines leave them open to attacks.Headteachers across the country have imposed or threatened sanctions with many citing 'serious safeguarding issues' or 'health and safety'.Parents of Herne Bay High School in Kent are the latest to have been sent a letter warning that pupils will be made to wear trousers if they persist in wearing skirts more than 4ins above their knees.In her letter, principal Claire Owen said she was worried some children were 'putting themselves at risk'.Speaking later on a local radio station, Dr Owen said she believed the girls were unaware that the way they were dressing could 'give out the wrong message'.The move follows that of Tollbar Academy in New Waltham, North East Lincolnshire, which is banning skirts from its uniform over health and safety concerns.The school's uniform policy states skirts should be no more than 2ins above the knee.But Judith Hackitt, chairman of the Health and Safety Executive, has branded the decision by Tollbar Academy as 'one of the worst examples we've seen of health and safety being used in completely the wrong context'.Peter Bradley, the deputy director of the children's charity Kidscape, said schools could be putting girls at greater risk by suggesting skirt length is a factor in sexual attacks as it could give teenagers a false sense of security.He told the Independent on Sunday: 'Records of attacks on women and girls over the years have not followed hemlines, up or down.'To judge this as a serious safeguarding concern is questionable. Girls who wear trousers will still be potentially at risk of unwanted sexual advances.' In the letters to parents explaining the bans, headteachers have also said that the girls' attitude to their skirts flouts uniform policy, wastes the time of teachers who have to tackle those issues and leads to pupils missing lessons because they are sent home to change.Mr Bradley said. 'A school that feels the need to ban skirts due to pupils not co-operating with staff requests should be more concerned about their pupils' behaviour rather than child protection concerns.'Even the national body that represents headteachers is wary of outright bans.Russell Hobby, the general secretary of the NAHT, said that schools have battled for generations against teenagers wanting to express themselves through their clothes by adapting their uniforms in whatever way they can.He said: 'Banning any item of clothing tends to harden opinions on each side.Creating a uniform code that permits a range of choices – so people can find something in which they feel confident – is probably the best approach.'