Jim, it must be said, is slowly losing his grip. Minor health issues mean he is away from school so much he has become a stranger to his classes. He spends long periods at his computer. He ignores his classes as much as he can, endlessly surveying TV listings sites. His neglect, and their boredom, evolves quickly into poor behaviour. They have started to insult him and taunt him.

We try to support him, but he is not interested. He feels at his age he has nothing to learn. All he wants to do is retire, but he can’t. So he plays the sickness game, always avoiding slipping into half pay. With this background, an “incident” was inevitable.

There was an argument with Calum. It was spiced with insolence and a lack of respect from a bored adolescent. Jim took him outside, where allegedly something happened. Calum says that Jim threatened him, pushed him, and then hit him.

Of course, Jim denies this. He is affronted. He wants action taken immediately against the child, whom he believes has brought his integrity into question through a false allegation.

But it has never been that simple. We have to carry out an investigation. The very thought of it is an insult to Jim. But we have to listen to what Calum has to say.

His mother comes into school to see us. Calum has not slept and is sick with fear, she claims. She wants revenge for her hurt little boy. She will give us time to investigate, but she is ready to go to the police.

We have to listen to Calum, but at the same time Jim feels that his professionalism is being denied. Even to consider an investigation is to imply that he is dishonest. But this is the world that we live in. Automatic deference to a teacher is a thing of the past.

Of course, it is inconclusive. There is a video camera in the corridor but the view of crucial moments is obscured and they can both use the images to support their point of view. Jim can’t have his reputation back; Calum’s family can’t have revenge.

At least a proper investigation has made Calum feel valued and deflates parental rage, though Jim takes no comfort from this. My view is that a poor teacher, while having a bad day, did overstep the mark. But I can’t prove anything, and I’m not sure I want to.

The rest of the class are convinced that Calum was hit. I have to change the timetable and take Jim out of there. Jim is on the road to disaster. And all I can do is watch and wait. I think it will happen again. Different class perhaps, a different incident, and perhaps a different outcome.

John Sutton is a pseudonym. He teaches in North Wales.