Maths teachers cited excessive workload as the main reason for leaving the profession, with many reporting evenings and weekends were dominated by work, researchers at London university’s institute of education found.

The small study comes after a larger analysis for the Government last week said one in four secondary maths lessons is taken by teachers of other subjects. The institute’s survey of 46 serving teachers, by Clare Tikly and Teresa Smart, found 11 per cent thought their health was suffering.

Among a smaller sample of 15 people who had left teaching, who were asked about their experiences in the profession, the figure was more than a quarter.

More than half of the survey respondents said weekend and evening work stopped them having a desirable lifestyle. Half of the head of maths respondents said that they did not intend stay in post.

The report included case studies which painted a devastating picture of the demands on some staff.

One 47-year-old returned to engineering five years ago after spending six years as a teacher in a comprehensive, latterly as a head of department.

The study said: “He was spending from 7.30am until 5pm in school on weekdays and working for the best part of most weekends. Driving home from school he would switch on a dictaphone machine to record his lesson reviews and plan the next lessons. He then worked at home until 9pm. One day his children said ‘we liked you more when you were an engineer’.”

The teacher said: “I love the profession. It is very challenging, rewarding, brilliant... but all the mathematics teachers I know are planning to teach for only five to 10 years.”

Charlie Stripp, chair of the teaching committee of the Mathematical Association, said: “The Government is focusing on trying to recruit new teachers, for example with golden hellos. This research suggests they need to consider what they can do to hold on to the ones they have already got.”