Safer Schools officers have been portrayed as Dixon of Dock Green figures, subduing rowdy classrooms with a wink and a wagging finger. But they are being blamed increasingly by youth representatives for clogging up courtrooms with minor incidents from bullying to petty theft.
The growing presence of Safer Schools officers means playground scuffles are resulting in more arrests and convictions than ever before, lawyers say.
Gavin Tranton, a police station lawyer, regularly deals with 14- and 15-year-olds hauled in following schoolyard scrapes. "These children are fingerprinted and DNAed and treated exactly as adults," he said. "The parents are often astounded that their children are questioned for six or seven hours just for playing a prank."
Gerry German of the Communities Empowerment Network says he regularly sees pupils hauled in for offences such as possession of just a pellet gun.
"Children as young as 13 or 14 are handcuffed," he said.
Mark Ashford, a lawyer who deals exclusively with youth crime, believes the Safer Schools officers are increasingly being used as intelligence-gathering operations, representing the "eyes and ears" of the police force inside the school. "They often help their colleagues on the local force with investigations if they think a pupil might be involved,"
The Safer Schools partnership has proved broadly popular since it was introduced in 2002 as part of the government crackdown on antisocial behaviour.
It was launched to combat a perceived explosion in school violence, such as the stabbing of football protege Kiyan Prince, 15, outside the London Academy, Edgeware, earlier this year.
A Youth Justice Board survey has estimated that an average of 40 incidents per school per year are prevented as a result of the scheme, and 79 per cent of pupils say it makes their school feel safer.
John Murphy, headteacher at John Paul II RC school in south London, said their school liaison officer helps with attacks on pupils and warns them of crime in the local area. "The police have been good to us. They get to know the pupils at risk of offending, provide drugs awareness training, and support us at public events," he said.
He admits that part of their job involves zeroing in on pupils suspecting of having committed a crime in the wider community.
"The local shopkeeper was attacked, and the police were able to monitor and find out which students might have been involved," he said.
But there is evidence that the occasionally combative approach of the officers is alienating teachers, pupils and parents. Tales of gung-ho behaviour from in-school officers have made occasional press appearances since the scheme was launched.
Last year, 11-year-old Earl Crump from Sheerness, Kent, was taken into custody and fingerprinted after threatening a pupil with a toy gun. And Mavis Twom Barimah's 15-year-old son was excluded from Bishop Douglass high school in east Finchley, after the police officer wrongly implicated him in an attack outside school, she claims.
"The police officer said my son had been implicated in an incident with a knife. In reality, there was no evidence. One of the youths had given his name, that was all. There was no investigation. The school decided to exclude him, and the officer rubber-stamped it because he fitted the profile of a young black man who might be involved in knife crime. Now he is in Year 11, and we are struggling to find him another school. I try to teach him not to hate the police, but this doesn't make it easy."
Shukria Mahmud was shocked when the police called to say her 15-year-old son had been arrested for refusing to leave school premises.
"I got a phone call one afternoon saying he was at the police station," she said. "The teacher asked him to leave. He refused, so they called in the officer, who handcuffed him and took him to the station."
It is easier for a minor to incur a criminal offence than for an adult. A child can receive only two reprimands; an adult can be cautioned indefinitely. The use of Asbos is increasing; if breached, they result in a criminal record for the young offender.
More schools are using Acceptable Behaviour Contracts, the next step up from an Asbo, meaning the slippery slope begins in the classroom.
"We have to disconnect law from order," said Will McMahon of the Crime and Society Foundation, who produced the school discipline study Checkpoint for Nonviolence. "Mostly where there is a discipline problem it's down to bad management. Criminalising children is not the answer."
Kathy Evans of the Children's Society said: "We are concerned at any avoidable criminalisation of children. It's crucial we avoid, where possible, involving children in the formal court process. Experience tells us that restorative justice can help to avoid prosecution and change behaviour."