I have been a teacher since 1971, and for the past 10 years I was a home tutor for pupils with complex behavioural and emotional problems attached to a pupil referral unit (PRU).

My experience of teaching there for a decade left a really sour taste in my mouth. There was constant nit-picking, fault-finding and criticism. I consider myself to be a strong person, not the sort you would expect to be bullied. The whole experience made me very angry.

One of the first major incidents happened in 2005. The headteacher called me into his office and said he was taking disciplinary action against me. I found out that I was being accused of being deliberately disobedient.

I had been teaching a child with obsessive-compulsive disorder. She would often lock herself in her room and refuse to let me in. The head told me to stop teaching her, and I did, but I had a good relationship with her family and had already arranged to take her to the Tate. After the visit - a one-off - I told a colleague about it and the head found out.

After going through the whole disciplinary process with my union rep for months, the head agreed that perhaps there had been some miscommunication and promised to do better in future. But this never happened.

I taught in pupils’ homes until the end of 2006, but I ended up being sucked into the PRU, where I was watched like Big Brother by the head.

He brought another disciplinary action against me in 2008. I had gone into the office on a day that I wasn’t working to speak to his line manager. No one was there, so I sat down to write a letter on one of the computers and must have left it on the screen. I was told that I shouldn’t have been in on that day or using the computer to write the letter to the line manager.

I went on long-term sick leave with stress and my GP told me not to go back to work until it was sorted out. Eventually a meeting was called in September and I went back to work afterwards, but the head was always checking up on me. I was even forbidden to take time off for a religious holiday, which had never happened to me since I started teaching.

Earlier this year, another disciplinary action was taken against me. I was accused of having private medical appointments during school hours and of not leaving cover work for someone. I immediately went to the office and showed them the work. The week before I had called the office to ask for directions to a pupil’s house, so they had accused me of being the only teacher to call the school for help.

The doctor again told me not to go back, and I wrote to the local director of children and family services to complain. When I came back to work, the school knew what I had done and I was hauled into the head’s office and verbally assaulted.

After that, I resigned. In the end, I thought my health was far more important. I had worked successfully in other schools across the world and I had never had to put up with that kind of behaviour. I think the problem was that I am very articulate and did not let it go. If I had been one of those people who puts their head down, it might not have escalated. But in my situation, working with vulnerable children, you would expect to have fully functioning, grounded people looking after them, which wasn’t the case.

Now I am at the age when I can retire, but if you are 40 and you are put under this kind of strain it is awful. I am going to keep fighting this for my colleagues’ sake, and society’s sake. I don’t want these terrible things to keep going on.

As told to Meabh Ritchie. Do you have an experience to share? Email features@tes.co.uk.