Teachers' leaders claim the price of turning around failing schools is stressed-out staff, high rates of sickness and low morale.

A survey commissioned by the National Union of Teachers claims that nearly two thirds of staff in failing schools are suffering from stress as they are put under pressure to make rapid improvements.

The survey by the National Foundation for Educational Research also showed that a third of teachers in failing schools had "significant periods" of sickness or stress-related absences in the six months after the inspection.

Over half the failing schools in the survey reported a decline in staff morale and an increase in resignations and a third said retirement through ill-health had risen.

This represents a "near intolerable cost" for teachers in schools put under 'special measures' after failing an inspection, says the union.

Headteachers are stressed by the fear of losing their jobs and teaching staff complain of extra hours spent in meetings related to the monitoring of failing schools, says the survey carried out by the National Foundation for Educational Research.

The survey was based on comparisons of staff in over 450 failing schools and over 450 non-failing schools.

The NUT's general secretary, Doug McAvoy, said that the excessive strains put upon staff would hinder efforts to improve schools.

"They lose good staff when they need to retain them. Stress levels among teachers become unacceptable and recruitment becomes near impossible.

"At precisely the point when schools need support in their teaching, they are hit by an avalanche of bureaucracy and by continuing public humiliation."