By Katherine Sellgren BBC News Online at the ATL conference

A teaching union is demanding the prosecution of children and parents who attack school staff.

The Association of Teachers and Lecturers (ATL) wants education authorities to bring private prosecutions if necessary.

They [schools] are places where violence should not be tolerated in any form

ATL general secretary Peter Smith

The ATL wants to see warning notices put up in schools - similar to those on the London Underground and in hospitals - saying the management will not tolerate violence against staff and will prosecute.

Its annual conference in Cardiff is also voting on a possible ballot of its members on industrial action over workload in the classroom.

On Wednesday the Education Secretary, Estelle Morris, is expected to tell the conference that "feckless parents" are to blame for disrespect shown to teachers.

She will say councils must make greater use of their powers to force violent parents to attend counselling or face court and a �1,000 fine.

Kicked and bitten

But ahead of her speech the union backed the case for local education authorities to pursue private legal actions in cases where the Crown Prosecution Service is reluctant to act after assessing allegations of violence.

Brian Waggett: Complained about culture of silence

The vote came after the ATL had 125 complaints from its members in the past year about physical abuse - mostly involving children.

The chair of the union's defence committee, Brian Waggett, said teachers were as important as other public servants who were better protected by their employers.

"An assault on a teacher should be serious - we're as important as other public servants, we have rights and our employers should recognise this," he said.

An assault on a nurse was not seen to bring her hospital into disrepute, yet teachers were often encouraged to remain silent about an assault as head teachers feared for the reputation of their school.

The union was often forced to pursue private prosecutions on behalf of members, he said.

One ongoing case involves a teacher in London who was injured in an assault at a bus stop by a parent angry about his child's detention.

'Zero tolerance'

The ATL's general secretary, Peter Smith, said such cases were not isolated ones.

"Schools are not places of violence - they are places where violence should not be tolerated in any form, be it verbal or physical," he said.

The union's head of legal and member services, Martin Pilkington, said teachers' employers should follow the example of London Underground where signs warned that anyone who assaulted staff would be prosecuted.

Patrick Nash of the Teacher Support Network - which provides counselling for teachers - said many were victims of low-level verbal aggression.

"Many of them complain that there's very little support in the school - either no procedures or no people in place to support them.

"Often they don't know what the mechanisms are by which they can take action on an incident of aggression."

Meanwhile the usually moderate union has not ruled out the possibility of strike action if the government does not improve teachers' employment contracts, putting a limit on classroom "contact" time, preparation and marking time.

The other two TUC-affiliated teachers' unions - the NASUWT and the NUT - will debate the workload issue at their conferences over Easter.