John was in my Year 10 class, a sweet boy with a problem right eye which sometimes watered and which he would close against bright lights. His form tutor said this had happened when John had been chopping wood on his parents’ farm when a splinter flew into his eye. His father had delayed taking him to the doctor until the next day, by which time the eye had become irretrievably damaged.

Although not academically gifted, John worked hard and co-operated wholeheartedly in class, so I wrote him a glowing end-of-term report. His father attended the parents’ evening and listened with an air of ill-suppressed disbelief to what I had to say.

He then proceeded to catalogue John’s failings as though John wasn’t there. When he did occasionally glare at the culprit, John flinched like a whipped dog. At length, the terrible monologue concluded, I was a gullible bleeding heart taken in by a stupid but scheming delinquent.

Fortunately, having written me off as an incorrigible simpleton, John’s father didn’t attend any more parents’ evenings. But I did gain one further insight into his parenting methods.

In the summer activities week, four other teachers and I took some pupils hiking in the Scottish Highlands, John among them. Normally a self-effacing lad, he flourished in an environment where he could display his country skills to his suburban peers - lighting a fire in the rain, helping the camping novices erect their tents.

But on the return journey he was worryingly quiet. When I asked him why, he explained that he had lost the plastic bowl he had brought from home. I offered him mine, but his momentary relief evaporated when he saw it was a different colour.

Surely that wasn’t important? When he looked at me with his brimming, mismatched eyes, I realised that it was.

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