Almost half of young teachers say mental health concerns could force them to quit the profession, research by the union NUT has found, with thousands citing heavy workloads and lack of support as a problem.

The union’s survey of more than 3,000 teachers under the age of 36 suggests more than four in 10 (45 per cent) may choose to leave within five years. Almost threequarters said they were working 51 hours or more per week, and nearly a quarter said they were doing more than 61 hours.

Responding to the survey, led by the NUT’s Young Teachers Working Party, more than threequarters (77 per cent) said their morale had declined since starting teaching, and a third (32 per cent) of newly qualified teachers specifically said they felt they had not received adequate support in their first years in the profession.

Kevin Courtney, NUT general secretary, said the fact that so many teachers were being forced to work 50-hour weeks was unacceptable. “Mental well-being is a key issue for young teachers and a decent work-life balance is therefore essential to facilitating good mental health,” he said.

“The government needs to accept its responsibility in this crisis and take positive steps to resolve the issues behind the problems of teacher workload that are clearly blighting the profession.”

Commenting in a stress debate at the union’s annual conference, the union leader said government policies were linked to rising mental health problems in the profession.

“Even more disturbingly, data on occupational suicides published by the Office for National Statistics in March 2017 shows that female primary and nursery school teachers have a heightened risk of suicide – they are 42 per cent more likely to commit suicide than the average woman,” he said.

“Although it may not always be possible to demonstrate a direct causal link between the stresses of teaching and such tragedies, possible links with excessive workload and stress must be taken seriously.”

Delegates at the conference in Cardiff voted to support action short of strike, as they emphasised that teacher stress was leading to poor learning conditions.