The human rights group Liberty has criticised Northumbria Police for using sniffer dogs in a drugs operation at a Tyneside school.

Officers were waiting for pupils outside Walker Technology College in Newcastle, to test the youngsters as they came into school on Tuesday.

Senior staff were aware of the operation but did not tell pupils or parents.

Liberty has condemned the move, saying it will lead to increased truancy and drive any potential drug users underground.

Police stayed outside the grounds of the college

No drugs were found in the operation, which Northumbria Police say is part of an ongoing project to crack down on drug use in schools.

Mark Littlewood, campaigns director with Liberty, said: "This was an insult to the students.

"The police should only be searching for drugs if they have reasonable suspicion and should not be acting in an ad hoc way.

"This type of operation is highly questionable and treats pupils as suspects.

'School property'

"It will just increase the likelihood of truancy and drive the problem further underground."

Walker Technology College deputy headteacher Linda Dalken said: "We are happy for the police to test children and we were glad when we heard none of our children had drugs.

"The police were not on school property so they didn't need to get consent from parents."

More than 1,300 children aged between 11 and 18 attend the college.

A spokesperson from Northumbria Police said: "Two drugs dogs were used to patrol around the college.

"Patrols are held across the region and no pupils stopped had drugs."