Schools should not be turned into fortresses and teachers into prison warders, heads have told The TES following the announcement of a government plan to use security scanners in inner-city schools.

Sally Coates, headteacher of Sacred Heart RC School in south London where a schoolgirl was stabbed last week, said she did not support the use of metal detectors.

“I am concerned about media perpetuating this myth of gang violence on the ground in south London,” she said. “It’s almost creating a self-fulfilling prophecy. Security arches lead to a fortress mentality.”

Sacred Heart, rated outstanding by Ofsted, was visited by Ed Balls, the Secretary of State for Children, Schools and Families, last year.

But last week, a 14-year-old boy was arrested after a fight in which a girl, 13, suffered minor stab wounds from a craft knife in design class. She was discharged from hospital the same afternoon.

Miss Coates said metal detectors at school gates would not have stopped a child grabbing a craft knife in class. “There are gangs in south London, but this was not connected with gangs,” she said. “This was an isolated incident, which I wouldn’t expect to happen again.”

Jacqui Smith, the Home Secretary, said at the weekend that she wanted to investigate the use of archway scanners which are commonplace in many American high schools. She did not say how the scheme would be funded; the Home Office’s Tackling Violence action plan will be published soon.

One of England’s biggest security firms, G4S, said it had failed to interest any schools or local authorities in its proposal to mount surprise weapon scans. It has been offering to take mobile scanners - which can cost pound;5,000 plus installation and staff training - around schools, using professional security guards to conduct the scans.

Douglas Greenwell, G4S’s marketing director, said security arches were a new cost for local authorities already cash-strapped.

But despite the Home Secretary’s apparent enthusiasm for security scanners, a spokesman said there was no evidence of an increase in the number of violent crimes committed by young people. There were more cautions and convictions, he said, but that was because of better enforcement.

A 2005 study estimated that 1.8 million young people had committed violent offences in the previous year, although most offences had not resulted in injury. While there has been much publicity about youth knife and gun violence, attacks in school are rare. It is also questionable if any would have been prevented by security arches.

- In 2003, Luke Walmsley, 14, was stabbed to death during a break in lessons at Lincolnshire’s Birkbeck school, the sort of small, rural secondary where such an attack would be least expected.

- In 2004, a pupil slashed a child’s neck at Waterloo primary school in Ashton-under-Lyne, Lancashire, prompting the school to ban pencil sharpeners.

- And in 2006, 15-year-old Kiyan Prince was murdered with a penknife while trying to break up a fight outside the gates of the London Academy in the north west of the capital. The academy owned two metal detector wands, which were used occasionally, but teachers preferred to rely on intelligence picked up from pupils.

Phil Hearne, who was principal at the time, said he supported security officers on school grounds and the new statutory powers for heads to be able to search pupils. But he had logistical concerns with security arches, saying it would not be possible to scan 1,000 pupils in the 15 minutes before school. Most schools had multiple entrances.

“It isn’t a cure-all,” he said. “We need to understand why youngsters are carrying knives. It’s not a school problem; it’s a societal problem.”

Sir Dexter Hutt, the executive head of a number of Midlands schools, said he was strongly opposed to security arches. “It would be a very unfortunate head who let their school get to that stage, instead of acting proactively earlier.”

Nigel Hoggarth, deputy head of the 1,300-pupil Mayfield School in Portsmouth, said security arches should be a last resort.

John Dunford, general secretary of the Association of School and College Leaders, said headteachers had never asked for security scanners in their schools.

Mick Brookes, general secretary of the National Association of Head Teachers, said: “There is already a fortress mentality. Our primary members wouldn’t see the need to go any further down that path.”

John Bangs, head of education at the National Union of Teachers, said that, while most teachers would not want scanners, for a few, where pupils were known to carry knives, they were a necessary evil.

Teachers on The TES online forum said schools were already seen as violent centres by their inner-city communities. No number of metal detectors would stop weapons being smuggled in, they said. “Stab vests will soon be part of uniform, as no one is prepared to take the bold steps to tackle the pandemic of delinquency in inner city schools,” said one.

But others were sceptical of the proposal. One said: “I regard the announcement of airport-style detectors as a ludicrous example of political spin and headline-grabbing by a Government led by news headlines, not principles.”

PUPILS SIGN HEADTEACHER’S PLEDGE NOT TO CARRY WEAPONS

Staff at Southfields Community College in south London will occasionally surprise pupils with hand-held metal detectors, randomly scanning them for knives and other weapons.

“If you have anything on you that you shouldn’t have, you might like to give it to us,” the pupils are told.” Red-faced pupils will pull out a pack of cigarettes.

Youths have been murdered around the south London borough of Wandsworth in recent years. Police have identified active gangs such as the Tooting Gang, the Wandsworth Terror Zone and Wandsworth Man Dem. James Smartt-Ford, 16, was gunned down at Streatham ice rink last year, and Eugene Attram, 16, was stabbed to death in a brawl a year earlier. Yet in the nine years that Jacqueline Valin (above) has been head at Southfields, she has excluded only two pupils for carrying knives. She said that the first step towards having a safe school was to work with the pupils and the community. As a sports college, Southfields tries to substitute the camaraderie of team work for the perceived comfort of gangs.

A community police officer teaches PSHE and most of the 1,300 pupils have signed a pledge not to carry knives. “My aim is for children to feel safe and secure and can learn,” said Ms Valin. She said it would be too expensive to put arches and staff at three entrances. “But if I had a serious problem with knives on site, I’d consider it,” she said.