It was the teacher’s second confrontation with an aggressive parent in a month. Another had insulted her in her classroom, during a parents’

evening. The teacher is now on sick leave.

Frank Hunt, secretary of the National Association of Schoolmasters Union of Women Teachers’ Oldham branch, went to the police station last weekend with the long-term supply teacher.

He told the union’s annual conference in Scarborough: “The police and the local education authority do not understand why the head did not report it that evening. The union has supported her; her school has not.”

Education Secretary Estelle Morris last week supported calls for employers to prosecute parents and pupils who abuse school staff, as she addressed the Association of Teachers and Lecturers’ annual conference.

During a debate on maintaining discipline in schools, Mr Hunt called for health and safety laws to be used to protect teachers in such cases. Members agreed employers sometimes needed to conduct risk assessments on violent individuals.

Mr Hunt, a geography and history teacher at Oldham’s Our Lady’s Roman Catholic high school, said the assessments forced heads to do something about problem pupils, adding: “They are more concerned with running multi-million pound businesses, joining management seminars and discussing policies rather than dealing with out-of-control youngsters.”

Margarita Taylor, a teacher at Ilderton primary in Southwark, south London, said that although she had the support of her head, the police and her union, a man who had attacked her was banned from school premises for just three weeks.

“I still feel anxious every morning to find this adult in my playground. The system has failed to protect me,” she said.

Executive member Ian Draper told delegates that guidance for health and safety inspectors made it clear that staff should be made aware of the background of violent pupils transferred from other schools.