Headteachers were warned by the Government yesterday against frisking pupils in the search for illegal drugs.
New guidance from the Department for Education and Skills, which had been trailed by Tony Blair as giving heads new powers to introduce random drugs tests, says body searches are "not appropriate".
Teachers' unions had been worried that the introduction of frisking could lay their members open to charges of abuse or assault by pupils.
The advice also warns heads that they must obtain consent - either from the pupil or their parents - before searching any of their personal property.
The guidance adds that if heads want to use sniffer dogs to carry out random testing - another move advocated by Downing Street - it would be best to bring in the police.
The advice says pupils should be taught about the dangers of illegal drugs and volatile substances - such as lighter fuel and glue. It recommends that all schools should be moving towards becoming smoke-free.