The government should pay for sniffer dogs to search schools, in an attempt to stamp out drugs misuse among pupils, a leading independent school head says.
Sniffer dogs can be used in schools if the head teacher wishes
Dr Anthony Seldon, head at Wellington College in Berkshire, pays a private company to search his school each term.
Dr Seldon said operating a zero- tolerance approach to drugs was the only way to stop pupils trying them.
The Department for Education and Skills said it was down to individual heads to determine the best strategy on drugs.
But Dr Seldon believes automatic exclusion for possession of drugs in school is the only way to stop young people dabbling in illegal substances.
At his fee-paying school, there is no second chance for pupils found with drugs.
"You shouldn't give children a second chance - it isn't helpful because they won't take the first chance," he said.
"If they are busted for drugs but not expelled, it's like giving them a badge of honour.
"There's no grey area here, it's black and white. We think drugs are sinister and not part of a healthy lifestyle."
Sniffer dogs are hired to search the premises at Wellington every term.
"The children never know when they're coming in and where they're going," said Dr Seldon.
Dr Seldon: Zero-tolerance is the only approach to drugs
"It helps them realise they can't get away with it. The amount of problems I've had has dwindled to insignificance."
Dr Seldon said the possibility of sniffer dogs uncovering drugs helped children refuse drugs.
"I'd advocate government money for it. Why aren't the police doing this?"
Some state schools in the UK do invite police with sniffer dogs in to check for drugs and in other instances, dogs have been brought in for "demonstrations".
Some local authorities have been concerned that a child might be falsely identified by sniffer dogs as carrying drugs because they have been contaminated by drugs in the home.
A spokesman for the Department for Education and Skills said: "Schools can employ the use of sniffer dogs as part of a range of strategies to detect and deter drug use, working in partnership with local police.
"We have issued comprehensive guidance to schools on a wide range of drugs education and prevention measures, including the use of sniffer dogs.
"It is of course an operational decision for heads and their local police to determine the best local anti-drugs strategies for their school."
At a drugs conference at Wellington College on Friday, Dr Seldon will criticise former Home Secretary David Blunkett's decision to downgrade cannabis.