A recent survey by the Headmasters' and Headmistresses' Conference of leading public schools showed that boarding schools take a stronger line than day schools. Just over half, compared with one in five day schools, expel students automatically for bringing drugs into school. Three-quarters of boarding schools but fewer than a third of day schools test for drugs, while very few, if any state schools use drug-testing.
Drug tests are generally used to check on pupils who have already been found with drugs, or are suspected of taking them.
The report, based on a survey of 2,400 pupils in 20 schools, found that slightly fewer 14-year-olds in public schools had used drugs than 14-year- olds in state schools.
It urged more flexibility in the way schools deal with drug offences. Many schools make a distinction between pupils found dealing in drugs and those simply in possession. Most expel pupils for dealing, but some would simply suspend a pupil found with drugs who had no previous record of drug-taking. Schools say they make exceptions for those who feel they have made a serious mistake.
Government guidelines for state schools, issued last year, pointed out that two out of three primary schools and one in five secondaries have no drugs policy.
They said some schools were too quick to expel pupils, which might make them more vulnerable to drug-dealers; expulsion is inappropriate unless pupils have been dealing, or had been repeatedly caught with drugs.
Drug-testing should be used only with the consent of pupils - or the parents of those under 16.