Teachers 'bully other teachers'
Bullying in school is a problem for many staff as well as pupils, according to a teachers' union survey.
The bullies are often other teachers who pick on their staffroom colleagues - with heads and senior staff alleged to be among the worst culprits.
The survey, from the Association of Teachers and Lecturers, says about a quarter of teachers have been bullied by another member of staff.
The union is calling for "robust" policies to tackle such instances.
Teachers report being "driven from their jobs" by bullying head teachers.
The survey of more than 900 primary, secondary, and further-education staff across the UK, published at the union's annual conference in Liverpool, showed that many teachers faced a range of workplace-bullying threats.
But among the teachers who felt they had been bullied, 50% said it was by a senior member of staff, compared with 25% by pupils and 23% by parents.
Anonymous comments revealed how staffroom bullying could undermine teachers.
"I didn't report it as the person bullying was the head teacher," said a primary school teacher.
"I was driven from a previous job by a head teacher who was suffering from stress. This manifested itself in her lashing out at everybody around her. I found myself on the receiving end of her behaviour," said a secondary school teacher.
Another teacher, a head of department in an academy, said: "I was persistently picked on and undermined by a colleague, and no member of the senior leadership team would take it seriously and take action.
"Following a poor set of results my whole department have been spoken to in a way I would never wish to be spoken to again. As a consequence two are leaving and others would if they could."
The survey looked at the type of bullying that these teachers had faced from pupils, parents and fellow teachers.
The most widespread forms of bullying were "negative comments" and verbal insults. But almost half of bullying victims claimed they had been intimidated - for example, being threatened or sworn at - and two in five reported "psychological abuse".
There was physical violence in just under 2% of cases.
The negative impact of such bullying included stress, and many of the victims had considered either changing jobs or leaving teaching altogether.
The union's general secretary, Mary Bousted, warned that schools needed to have policies in place to protect staff from workplace bullying.
"It is unacceptable for any staff to be bullied by colleagues, and schools and colleges need robust policies in place to pick up any problems and deal with them promptly.
"It is not good enough to just tackle the symptoms; schools and colleges also need to tackle the cause of the bullying. In the case of many education staff, they are under too much pressure in their roles and this needs to be addressed," said Ms Bousted.