Ten per cent of headteachers have been assaulted by a parent or carer during the past five years, according to figures to be disclosed later this week.
Most of the assaults took place on the school premises – often when the parents came to complain about a child being excluded from school. They include cases of heads being hit by chairs thrown by angry parents and one being subjected to "a serious kicking attack".
"I was badly bruised and had difficulty walking for a couple of days," he told researchers.
One female head has described how a parent had scratched the word "bitch" on her car. She said: "It wasn't an assault on me but it left me very, very shaken and traumatised. Police orders were required to protect the school from the parent."
The cases are reported in a survey of more than 500 heads to be published by the National Association of headteachers at its annual conference over this bank holiday weekend.
In an interview with The Independent today, Russell Hobby, general secretary of the NAHT, said the mantra of "parent power" repeated by successive Governments may have led them to believe they can have more of a say in the running of their school and be more aggressive in their demands.
"We may have excluded their child temporarily from school or sometimes banned them from being on the premises," he said.
"I'm not against parents having a real say in the way their schools are run but sometimes you have to make choices and take decisions that displease."
The figures come to light just as the Government has launched its own plans for a crackdown on bad behaviour in schools. However, the package concentrates on dealing with pupils giving greater powers to teachers to confiscate items such as mobile phones.
It also gives more power to heads over exclusion – allowing appeals panels against exclusion only to review cases rather than order youngsters be taken back into the classroom.
But it has little to say about what action to take against unruly parents although schools have been encouraged to get parents to sign up to good behaviour contracts in a bid to get both pupils and parents to recognise the disciplinary rules of the school.
Further cases from the survey include one head who said she had been "punched in the face, bitten, kicked, spat at, had a hand put down her T-shirt to grab her boobs and had her hair pulled".
Another said he had been struck repeatedly and "whipped with a coat". "A table was thrown at me," he said.
One former general secretary of the NAHT, David Hart, has called for heads to have the right to expel the children of violent parents from school. He said that he believed it was "perfectly proper" to expel a child once a threat had been made. He said: "The relationship between a family and a head has fundamentally broken down if violence is resorted to and that child deserves a second chance elsewhere."
At the time of his comments, the NAHT had dealt with 54 cases of violence and abuse against heads in a term. These included 10 threats of violence, five assaults, seven cases of verbal aggression and two parents having to be banned from school premises.
A spokeswoman from the Department for Education said: "We want to give parents a good choice of schools in their area. But this, of course, does not excuse aggressive behaviour towards school staff by a minority of parents.