By Gary Eason
BBC News Online education editor, in Llandudno
The term "strong leadership" in schools is often just a cover-up for bullying management, teachers have said.
Long hours and bullying go together, teachers said
Such "negative and destructive" behaviour by adults could have "dire consequences," the annual conference of the NASUWT teachers' union was told.
These included breakdown, job loss, attempted suicide - and in some cases even suicide, said a member of the union's national executive, John Mayes.
Delegates said they viewed the rise in workplace bullying with alarm and called for a high-profile campaign to highlight the issue.
They wanted to expose the lengths to which some governing bodies, education authorities and church leaders would go "to cover up these practices".
Mr Mayes said management bullies included those who thought it was expected of them, they were the "purveyors of macho management".
Others did it as a form of punishment.
Some were "pathological" - they liked it and did it for pleasure.
But he said all were having trouble doing their jobs, they were inadequate or just could not cope.
Many of their victims did not seek help, often because they blamed themselves or did not realise what was happening to them, or feared the repercussions.
"Let's wage war on the bullies," he said.
Long hours culture
Peter Johnson, a delegate from Bromley in Kent, said it was no coincidence the rise in workplace bullying had come at the same time as the pressure in schools from league tables and Ofsted inspections.
Workload was another factor.
"The long hours culture and bullying go together," he said.
Peak District delegate Alison Sloan said some of the worst offenders were primary school head teachers who themselves had never taught the literacy and numeracy strategies.
"So all they can do is criticise," she said, to applause.
"They can't give advice to those who ask for help, so to cover up their own inadequacy they shout at them."
Others cited bullying in the form of teachers being given impossibly long lists of tasks to do, or impossibly tight deadlines, denigrated in staff meetings - or simply being ignored.
A recent report by the Teachers Support Network on calls to its helpline said one of the biggest single reasons people sought help was conflict with colleagues - especially managers.
A member of the NASUWT executive, Sue Percival, said the union must work with employers to develop comprehensive anti-bullying strategies, with independent panels to investigate complaints.
"Those who can, do - those who can't, bully," she said.