Kyle had become one of my Year 7 student niggles: lunchtime detentions here and there and all his teachers telling me about his antics. I met his mother on several occasions and it was always “Not my Kyle.” She said his detentions were for all sorts of “silly stuff”, or “I’ve had me belly-full of you lot”. I took this in my stride and said perhaps we should meet after school one evening. It did not go well as she appeared with three children under five, a buggy and sausage rolls. But the school agreed that only I would contact her, to stop all the phone calls from his subject teachers.

Within a week an incident occurred during a lesson with a very naive NQT. It was her first time teaching a PSHE lesson about safe sex. For the first time, Kyle had been a star pupil and knew just about everything there was to know. But as the red-faced NQT explained, at the end of the lesson she had found Kyle with a vibrator thrumming its way along the bench.

I had waited for this moment. I asked Miss Hill, the NQT, to stay in my office while I made a phonecall to his mum.

“Hello, is that Mandy Smith? I have Miss Hill here regarding something in the sex education lesson today.”

“Oh? What you after him for now?”

“Mrs Smith, Kyle has been demonstrating how a vibrator works in the lesson. It is silver ... ”. At that point there was silence followed by a tirade of expletives explaining what she would do to Kyle when he got home. And then: “Can I come and pick it up? It’s been missing for a week.”

I got her to agree to a meeting with just her and her boyfriend straight away. It was months before I had to see Kyle again.

The writer is a former teacher from North Yorkshire. Send your worst parent stories to features@tes.co.uk and you could earn #163;50 in MS vouchers.