John Illingworth (above), 55, is still officially head of Bentinck primary and nursery school in the city of Nottingham, although he has been off sick with stress since last November and has applied for early retirement.
Bentinck was his third headship. Mr Illingworth, a former president of the National Union of Teachers, describes the experience of becoming ill through overwork and the effects of the stress that he says had built up over years:
"There were a few weeks at the end where I was really unwell, mentally. I couldn't make decisions, couldn't prioritise, I was wasting my time doing trivial things when there were important things to be done. On one occasion I was almost tempted to grab hold of a kid. I was quite emotional sometimes, and you can't be bursting into tears when you're dealing with a stroppy child. My wife is a teacher at the same school and she could see what it was doing to me. I decided to take some time off.
"I've had fantastic support from the medical profession; they encourage you to take a long look at yourself. In March, I decided I wouldn't go back.
All the advice is that if I do, I'll have greater problems in future. The diagnosis is that I have burn-out. At my worst, last winter, I couldn't cope with children being in the doctor's waiting room. I had to wait in the car park.
"I was 31 when I got my first headship, and running that first school was a very different job from running the last one, even though they are almost next to each other. The pressures on headteachers have grown to a point where they are ridiculous. I've known heads, who hadn't realised they were getting ill, do all kinds of things: making poor decisions, bullying staff.
It can manifest itself in different ways. My character changed, from being easygoing to being quite difficult. One of my sons reckons it has been 10 years since I have been myself.
"When I was still working, I was lucky to get three or four hours' sleep. I used to get up and read. I developed a kind of eating disorder; I put on four stone in the last job, comfort eating at the end of the working day.
I've lost two of them since going off sick.
"For the last two years, there was no time when I wasn't physically or mentally at work. I didn't have anything else. I gave up golf, thought about work while I was gardening, whatever I was doing. The new Ofsted arrangements mean that you are constantly evaluating what's going on in the school, and I think they are incredibly damaging.
"After my speech at the NUT conference, I had nearly 250 emails, letters and calls. But I have had no messages of sympathy from my employers (the City of Nottingham LEA, not Nottinghamshire). I think it's wrong that people who've worked very hard in difficult circumstances for a long time should be punished by having their career end in this way. The inner city brings its own pressures, but I don't think there's any such thing as an easy primary headship.
"I loved teaching for years and years; there are wonderful times, a lot of upsides. It's only quite recently that it's become unmanageable. I did training on stress management, time management, assertiveness. I used all the strategies I know: delegating tasks and responsibilities, getting exercise. If I could tell you what heads should do to protect themselves, I wouldn't be here now.
"Peer support can help; for some, it's quite a lonely job. But I think a lot of this is sticking plasters. We won't really do anything about mental illness in teachers and heads until we start really looking at the causes, the load of pressures and initiatives that primary heads have to deal with, plus the fact that everyone wants access to you. There's a limit to the amount of pressure you can cope with."