Parents could face prosecution if they threaten or abuse teachers as part of a get tough approach on school behaviour.

Mirroring the "zero-tollerance" approach begun by the NHS to counter verbal threats and violence towards staff, the government is stepping up its efforts in response to complaints by teaching unions about the rising incidents of agressive parents bring disputes into schools.

The measure was discussed by the prime minister on Tuesday at a school behaviour seminar in Number 10 that brought together ministers and teachers from some of the country's toughest schools.

Number 10 said the summit indicated the prime minister's strong support for teachers and was a demonstration of the government's "determination to tackle disruption and truancy".

"These are obviously problems that can bring down educational standards," said the official spokesman.

"The prime minister's view is that teachers have an absolute right to be treated with respect and have an absolute right to feel safe in their work."

The meeting checked on the progress made since the first summit which was held in April.

Pupil exclusions, though now at the government's target, are running at around 8,000-a-year and teaching unions continue to highlight the problem.

Education minister Estelle Morris, herself a former teacher, sees it as key to many of the other problems of under-performing schools leading to a higher turnover of pupils and staff, and a greater degree of social deprivation.

Morris is on record as saying that the biggest problem in education was not social exclusion or a lack of funding but "two badly behaved children in a classroom".

The education secretary has cited the problem as being one of the key reasons behind the difficulties in teacher recruitment - no graduate will contemplate a career in education while there are stories of classroom violence.

Teaching unions welcomed the announcement. "This guidance to schools will be welcomed by teachers round the country," said NUT general secretary Doug McAvoy.

"The NUT's research shows that a small but growing number of pupils and parents believe it is acceptable to harangue and harass teachers, sometimes turning into physical assaults. It is not."

"Whilst the guidance and information from the government will be useful, schools need to be assured that there will be a speedy response from the police if the need should arise.

"There is also a dearth of statistical information on the number of such incidents and who carries them out. The government should be collecting this information which is necessary if we are to understand the nature and scale of the problem.

"Society is more aggressive and less respectful. Schools cannot shut this behaviour out at the school gates. But teachers and pupils must be able to go about their work free from fear of verbal abuse and assault."

Phil Willis, the Liberal Democrat education spokesman, described the threat of court action against parents as a "paper-thin solution" to a deep-seated problem.

"Parents who are violent towards teachers are often the same parents who show violence towards their children. Schools require resources to work with families to modify behaviour so that parents can support children in their learning," he said.