The Abbey School in Faversham, Kent, last week became the first state school to administer the controversial tests. Twenty pupils had mouth swabs taken as they arrived for the new term and the school plans to continue randomly testing up to 20 pupils a week as well as staff members.
Drugs charities and civil liberties campaigners have voiced strong opposition to the practice of testing children, while parents and teachers have condemned rolling it out for teachers.
But head teacher Peter Walker revealed that many other state schools had expressed an interest in the scheme.
"A lot of schools want to be kept informed," he said. "I've already had interest from Manchester, Preston, Bristol, London and Kent itself and that's just in the UK. I've also been contacted by schools in Australia, Kenya, India and Spain and asked for advice and help."
Walker said the aim of the scheme was to support children with problems rather than punish them, and insisted that pupils testing positive would not be expelled unless they were found to have been dealing drugs. He said there would be no pressure on children to take the test and that no child would be tested without their parents' consent.
The school sought permission from parents of all 921 pupils at the school and 85 per cent of the 689 replies so far supported the scheme. But less than half of its 120 staff said they would be willing to take a test.
The 43 who agreed will begin to be tested this week.
Martin Barnes, chief executive of drugs charity DrugScope, said there was no proof that random testing was a deterrent, while civil rights group Liberty said: "The only institution that has regular drug testing is prisons."
Margaret Morrisey, spokeswoman for the National Confederation of Parent Teacher Associations, said: "There would be awful trouble if this was introduced in most workplaces. The original idea was to try and reduce drug taking by youngsters. We're not totally comfortable with that and to slip in tests for staff through the back door is not fair to them and very much impinges on their civil liberties."
