I was in two minds. I was pleased Dale’s dad had volunteered as a parent helper, but on the other hand ...

Dale’s dad was an odd man. He was small and squat with a chubby, childlike face - the opposite of his son. Our meetings were awkward encounters about Dale’s deteriorating behaviour.

I had done two preliminary visits to the out-of-town primary school where their nature reserve beckoned with the promise of pond dipping, bug hunting and the chance to paddle and explore a shallow river.

Six parent helpers arrived on time. Dale’s dad appeared just as the coach was about to depart, looking sweaty and harassed.

My preparations had been impeccable. I issued each parent with a map of the school grounds and highlighted the short path to the river, even though its location was perfectly obvious.

At the end of the day, as the sun dipped behind the trees, the coach driver could not be placated. We were supposed to depart at 3pm sharp, but Dale’s dad and four children were missing.

I was at the point of dispatching a search party when the children appeared, unaccompanied. The coach driver had not anticipated a rescue but volunteered - only to hurry things along. Dale’s dad had become hideously lost and was stuck at the bottom of a steep grassy bank, unable to manage the climb. The children had fended for themselves. He eventually emerged in his default setting - sweaty and harassed - soaking feet and clothing dishevelled.

To add to the driver’s eventful but increasingly unhappy day, Dale, his dad and two other children were violently sick on the return trip. Needless to say, that was the last time he volunteered.

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