Delegates spoke of attempted suicides, of deaths after colleagues quit on health grounds, of a teacher who “disappeared”, leaving a home and two young children, of breakdowns and resignations.

They heard that few teachers were now able to stand the stresses and strains of the job until the age of 60 or 65. Latest Government statistics reveal that about 1 per cent of teachers and lecturers retired on the grounds of ill-health, with the number increasing in the past decade by 226 per cent, from 2,449 to 5,535.

“Much of the job satisfaction that teachers enjoyed in the past has evaporated,” said Alan Draper, from north Suffolk, where the number of teachers retiring early on medical grounds has risen from two in 1987 to 17 last year.

“We are working to a prescription with the spotlight of accountability blinding and exhausting us. The stress is such that it is no wonder that so many teachers are just burnt-out.”

Jules Donaldson disclosed a “horrific” catalogue of casualties from his own “average” school in Sandwell - one colleague had died after taking early retirement through ill-health, while three others had retired on medical grounds.

Two other members of staff were long-term absentees, probably likely to retire through ill-health, and there had been an attempted suicide and two resignations - one only two weeks ago.

“This is a life and death issue,” he told the conference. “Unless we stand up and do something about it, there are colleagues who will not live to see their natural retirement.”

Dorothy Baker, a member of the union’s national executive, spoke of a teacher who died within six weeks of leaving on grounds of ill-health, and another who “simply disappeared”, leaving two children.

She said a 46-year-old teacher had cried for more than three hours on the several occasions she had seen him, and said: “He is a broken man because he is a teacher.”

The union, which agreed to seek compensation for teachers forced out because of stress, highlighted “aggressive” inspections by the Office for Standards in Education and the crisis in funding as particular flashpoints.

And Mr Draper, from Pakefield Middle in Lowestoft said: “Currently, I have at least one type of after-school meeting every week, often two. There are staff meetings, curriculum meetings, pastoral meetings, liaison meetings with teachers from other schools, meetings with parents and so on.

“There is likely to be an OFSTED inspection at the school soon, so we have to have all our paperwork in order. Schemes of work, assessment policies, marking policies, a school behaviour policy, a sex education policy, a SEN policy and countless others.”

Delegates also identified “unnecessary” stress caused by headteachers, with some - though not his own - described by Mick Mumford from Harrow Way comprehensive in Andover as bullies.

He appealed to heads of departments, deputies, heads, advisers, inspectors, chief officers and Government to work together.

And Mr Mumford added: “Finally, my family asked me to say this because they know what it is like to look after someone who has had a breakdown. Please take care, I’ve been there and it is not nice.”