Head teachers demanded more protection yesterday from so-called "parents from hell", saying they were their biggest worry after Ofsted inspections and paperwork.
They called for increased protection from the police and the courts after it emerged that more than two-thirds of heads surveyed by the National Association of Head Teachers said their work had been affected by violence from parents. David Hart, the association's general secretary, said the authorities were often unwilling to prosecute offenders and those who did go before the courts received light sentences.
Headteachers told of incidents involving knife-wielding parents and gangs armed with bricks. In a recent case, Mr Hart said, a father assaulted a head teacher and "got away with a community service order".
Mr Hart said: "We need a deterrent. Everybody working in a school is entitled to protection from violence. The sad fact is incidents of violence and levels of abuse from parents are on the increase."
James Bishop, headteacher of St Mary Redcliffe primary in Bristol, saidthat police did not arrive until 90 minutes after being called recently to help deal with a gang of youths armed with bricks who tried to steal a teacher's car. Mr Bishop said he had also had to make a citizen's arrest after being confronted by a drug addict who had broken into the school.
He said that problems had reached the point that staff arranged to leave school together each evening to ensure safety in numbers.
Mr Bishop gave his account as the association reported the results of its survey of 3,200 heads on the pressures of the job. The author, David Osborne, a former secondary school head, said: "In many many cases heads have eventually had a breakdown and leave work because they just can't take it any more, because they have had some really, really difficult customers.
"A total of 2,296 of the 3,200 surveyed responded to the question about violence, which indicates that they did have experience of this."