Barely one in 10 physical assaults on staff or pupils is accurately reported to local authorities, meaning action is not being taken to tackle violence in schools, a teaching union has warned.
The NASUWT said that teacher safety was at serious risk because of widespread failings by schools to report violent attacks, verbal abuse and accidents.
The shocking figures come in the same week it was revealed that teachers are also suffering intimidating attacks outside school, with property and vehicles being vandalised.
Staff have endured hoax phone calls, had their cars keyed and, in one example, a female teacher had the word "bitch" painted on her garden wall, the Association of Teachers and Lecturers annual conference in Liverpool was told.
The figures on under-reporting incidents have raised fears that patterns of violence are not being picked up, leaving staff and pupils vulnerable to problems that could have been avoided.
Only 12 per cent of physical assaults on staff and pupils are accurately reported to local authorities, according to a survey of the NASUWT's regional officers. A further 53 per cent of respondents said that assaults are under-reported or not reported at all. Only 5 per cent of verbal assaults are accurately reported, according to the poll.
The survey also highlighted problems in the accurate recording of accidents and near misses when injury was narrowly avoided.
"This is putting people at risk because if incidents are not properly reported you can't review them, look for patterns and develop robust strategies to stop them happening again," said Chris Keates, general secretary of the NASUWT.
"It gives rise to questions about why schools are doing this. In some the answer is that they are afraid it will damage their reputations.
"There is something wrong where reputation is put before the health and safety of pupils and the workforce.
"It is another example of where schools are not carrying out their statutory duties. There is a fundamental problem where public institutions feel they are above the law."
Just 3 per cent of near misses are accurately reported to local authorities, respondents said, despite advice from the Health and Safety Executive that all incidents should be recorded and monitored.
Ms Keates said: "The figures do not mean that schools are not dealing with problems at all, but it does mean they might not be dealing with them appropriately," she said.
The findings, which come from a survey of the union's 102 representatives based in different local authority areas, will be published at its annual conference in Bournemouth next week.
The results are despite the fact that seven in 10 local government respondents said they had policies to ensure that all incidents, accidents and assaults are reported, although a third of councils refused to answer the question.
A report on teacher safety carried out by the NASUWT last year found that one in six teachers had been physically assaulted by a pupil and half of teachers had been verbally abused in the past two years.
John Dunford, general secretary of the Association of School and College Leaders, said: "It is more important that schools deal with incidents than jump through bureaucratic hoops in submitting reports to local authorities, which will then do nothing about them."
Call for protection
Schools should adopt a policy of zero-tolerance on violence to protect staff from unruly pupils, the Association of Teachers and Lecturers said this week.
Teachers are being terrorised with attacks on their homes and cars. And inside school there is a "daily struggle" to deal with violent and disruptive pupils, the union's annual conference heard. In the past year, the ATL has received 146 claims for damage to teachers' property at school.