The headteacher of a Kent school which introduced random drug testing of pupils believes it contributed to an all-time high in GCSE pass rates.
Mr Walker wants to increase random drug test at his school
The Abbey School in Faversham, which began testing pupils at the beginning of 2004, is believed to be the first in the UK to do so.
This year, 40% of pupils achieved five good GCSE passes, compared with 26% last year and 32% the year before.
Head Peter Walker said he now hoped to extend drug testing to more pupils.
Mr Walker said the testing was one of a number of factors which had given the school its best year ever.
"We have had a very stable staff, very high performing students who have tried very hard, new building projects and morale is at an all-time high," he said.
"I feel that the drug testing has helped people feel much safer.
The school has seen a marked improvement in GCSE pass rates
"It has had an effect on contributions in the classroom and on behaviour - with far less disruption and that kind of thing," he said.
The mixed, non-selective school takes pupils aged from 11 to 19.
From the spring term, 20 names each week have been selected by computer to have mouth swabs taken.
The swabs are sent to a laboratory to be tested for cannabis, speed, ecstasy, heroin and cocaine use.
Out of 270 tests conducted so far, only one was positive. One pupil refused to take the drug test because he admitted he was a cannabis smoker and did not want to stop.
In both cases, the pupils were interviewed in the presence of their parents and "appropriate" action taken.
Mr Walker told the BBC news website he would not expel pupils unless they were drug pushers, which did not apply to either of these students.
He said he wanted to increase the percentage of pupils whose parents and guardians had given permission for the testing.
So far, 14% had refused permission, which included children in the care of Kent Social Services.
"I can understand that there could be fears about infringing human rights, civil liberties and that kind of thing, but we have been very careful about that," he said.
He said there had been an incredible amount of interest in the scheme from schools elsewhere in the UK and around the world, but no other school in Kent had made inquiries.