It’s assumed that they lead an idyllic life with well-behaved pupils and long holidays. Sadly, the reality for some independent school teachers is that they are often exhausted and exploited.

“People need to know that although the pupils are wonderful, the working conditions can be impossible,” says Elizabeth Steel (not her real name) .

“I am heartbroken to be leaving teaching, but the stress has made me so sick that I am having to take ill-health retirement.”

Ms Steel, who taught science at an secondary school in Yorkshire, says that pupils at the school worked a 52-hour week with an extended day and Saturday school, so staff were expected to keep pace. When she went part-time, Ms Steel was told that she would only be paid for the lessons she taught, yet her timetable still required her to spend most of the week, including Saturday mornings, at the school. She was also expected to cover for absent colleagues without pay.

Recent research by the Association of Teachers and Lecturers has found that few private schools have any formal agreements on teachers’ workloads. As a result, staff are finding it increasingly difficult to maintain any sort of worklife balance. Of the 1,000 teachers surveyed by the association, which has 18,000 members in independent schools, 85 per cent said that excessive workload was having a negative effect on their home life. Sixty per cent worked more than 50 hours a week, 35 per cent felt exhausted and stressed every day because of their heavy workload, and 30 per cent said they had no time for a social life.

One 46 year-old who teaches English at a boys’ school said: “I often don’t know what my finishing time will be as sometimes at short notice I’m expected to teach the under-14 rugby team after school, as the school’s PE teacher is only employed part-time. This results in me not getting home until mid-evening. By then, I don’t have the time and energy to do any non-work-related activities other than eating or sleeping.”

Teaching at a boarding school can destroy boundaries between home and school life, as one head of pastoral care at a secondary school found. He said: “It is expected of me to have an open-door policy to enable students with problems to come and talk to me at any time. This happens fairly often and it’s not unusual to find me counselling a pupil late into the evening.”

One female history teacher who lived in at her school discovered that she was not only expected to do a weekly boarding duty but also supervise the common room and dining hall in the evenings. In her case, the school considered that its beautiful setting was ample reward for unpaid duties.

“My school functions on the assumption that I should be ‘willing’ to work beyond the working day and that I should count myself lucky that I get to work and live in a school which is situated in such a lovely part of the country,” she said.

Sixty-five per cent of the private school teachers were expected to perform tasks they felt should not be the duty of a teacher. These included administration, lunch and playground duties, photocopying and extra-curricular activities, as well as washing and ironing PE kits.

Although teachers in the independent sector enjoy, on average, four weeks more holiday a year than their state school colleagues, extra-curricular activities and even holiday clubs will often form part of their contracts.

Most reputable independent schools follow model contracts devised by the Association of Governing Bodies of Independent Schools, but the ATL advises teachers to ask for a copy before they accept a new job.

Unfortunately, some schools don’t issue contracts and they are not bound to contribute to the Teachers’ Pension Scheme or use national pay scales.

After new managers took over at one struggling Derbyshire girls’ school, for instance, staff found they were facing salary cuts of up to pound;15,000.

Elizabeth Steel had no contract for the first six years at her school, and was then given one which her lawyer has since described as illegal.

“Some independent schools think they’re above employment law,” she explains. “At my school, jobs and promotion were often awarded without outside advertisement and without interviews. If you complain, you are just given a worse timetable.Unlike the state system, there is very little solidarity among the staff, as everyone is frightened that they will be next.”

Staff are sometimes deterred from protesting by conditions in their contracts. Ms Steel’s states that she must not do anything which would bring the school into disrepute.

Ms Steel blames many of the problems on the narrow experience of some independent school staff. “Independent school managers tend to go from private school to university to private school and they live in an unreal world,” she said.

The ATL has now called for improvements in the rights of teachers in the private sector. In a resolution passed at its last annual conference, the union said the teachers should have the right to at least a day and a half of undirected time in each seven days. The union is also campaigning for staff membership of the Teachers’ Pension Scheme, family-friendly and sickness benefits as good or better than those in the state sector, a retirement-age policy and action to improve teachers’ workloads.

None of the teachers who spoke to ‘The TES’ or the ATL wanted to be named