Stressed teachers are hiding signs of depression over fears that bosses will mark them out as a “weak link,” education union ATL warned yesterday.

More than a third of 900 ATL members surveyed said they have noticed an increase in mental health problems among their colleagues in the past two years.

And almost half admitted hiding health issues from bosses over fears they could be sacked.

Almost seven in ten teachers revealed they have been forced to keep mental health issues to themselves, while six in ten reported hiding physical health problems.

One department head at a Newport college was clear that “your job will be at risk” if you complain about pressure and unrealistic targets causing problems.

Another head of department in a Kent secondary school explained: “It is no good telling the management about your hidden disabilities because they will consider you as a weak link.”

The exposé of stigma over mental issues will raise fears over the impact of Education Secretary Michael Gove’s introduction of performance-related pay — which will be set by individual head teachers from September.

ATL issued the wake-up-call to rising mental health problems in Britain’s classrooms ahead of a debate at their annual conference today.

General secretary Dr Mary Bousted said: “Education professionals do more unpaid overtime than any other group and are put under constant intense pressure to meet targets, with excessive observation, changes in the curriculum and Ofsted inspections.

“Those working in education need to be supported better, with schools and colleges making adjustments to their jobs and working conditions where necessary.”