The good impression he’d made on people previously, and at interview, was a carefully constructed front. He did the minimum of official work, preferring instead to do high-profile favours for teachers and governors.

Then he spent ages whingeing to the head about the obstacles preventing him from doing a good job.

The head, accustomed to caretakers who were open-hearted, genuine friends of schools, was at her wits’ end. She was being put on the back foot by a person the like of whom she had never had to deal with before, but who was essential to the running of the school. “You’re the head,” she said to herself. “How can a caretaker get you stressed like this?”

What was needed, she felt, was a confrontation, perhaps a disciplinary warning. But the case would be tenuous. The work was being done, albeit to a minimum standard, and forcing the issue could end with the caretaker, supported by his union, coming out best.

It was the head’s American-born elderly mum who had the best advice in the end. “I guess it’s time to put the dog on the porch,” she said. The phrase, she explained, came from Texas where, if a dog was ill-behaved, you didn’t have a battle (“Bad dog! Thwack!”) but put the miscreant out on the porch, put food out, got on with life and waited to see what happened.

“Don’t talk with the guy any more than you have to,” said the mother.

“Leave him written instructions and don’t get into arguments. Be the cold and distant boss. Then wait him out.”

So that’s what our head did. As soon as the decision was made, she felt freed from the burden of uncertainty. She was relentlessly polite, cool and direct, avoided discussion, never responded to gossip, played everything by the book. Within a year, the caretaker was gone, seeking someone else to manipulate. The dog, starved of attention, had fled the porch.