Peter Walker, a former headteacher who implemented the country's first random drug-testing for pupils, will speak today at a conference at Wellington college in Berkshire to discuss how schools can tackle drugs.
He is worried that only four out of more than 100 secondary schools in Kent have volunteered to take part in a government pilot into random testing.
Mr Walker, who is now a drugs consultant for the Department for Education and Skills, will tell the conference that schools should not fear they will appear to have a drugs problem if they take precautions.
"All schools have a drugs problem. There's not a secondary in the country that doesn't," he told The TES. "If schools got together and all decided to do something, we could seriously cut down the number of drug takers in this country. Unfortunately, very few schools have taken up the chance to do random testing."
The conference comes in the same week as an independent report, commissioned by the UK Drugs Policy Commission, found that the fight against hard drugs is being lost, with increasing numbers of young people using cocaine and heroin. Concern is also growing about the use of skunk, a super-strength variety of cannabis.
Anthony Seldon, master of Wellington, said that he had introduced a zero-tolerance policy on drugs at Wellington college after seeing how cannabis had destroyed the lives of friends, leading them to depression and suicide. "What is freedom if freedom means spending life depressed, psychotic or in a mental home?" he said. But Martin Barnes, chief executive of the charity DrugScope and another speaker at today's conference, is expected to say that pupils involved in drugs should only be excluded as an "absolute last resort" - and only then when there are other reasons.
"Overall, illegal drug use among 11- to 24-year-olds has fallen in recent years," he said. "It is important to emphasise this, as there is evidence that many young people overestimate levels of drug use among their peers."