Tom’s teacher, Mr Bouncy, is very good at publishing such warnings. A child only has to cough for him to be on the word processor churning out yet another letter in that large, friendly typeface teachers reserve for the parents of young children.

And yet I’m worried how much Mr Bouncy misses. That plague of dropped aitches, for instance. We were totally unprepared for the day that Tom came back talking like an extra from EastEnders. “Dear mums and dads! It seems that some of the children in your sondaughter’s class are affecting Cockney accents this term. If this condition persists you may want to contact a speech therapist.. .”

Or the time that Power Rangers became all the rage. “Dear mums and dads! It seems that some of the children in your sondaughter’s class have taken to kicking each other in the windpipe.”

My wife, I know, would certainly have appreciated being warned that the word toilet was infecting Tom’s class. She had looked round many schools - in both the private and public sectors - before settling on St Jude’s because it alone seemed to offer no non-U words on the syllabus. Alas, within weeks, Tom had brought home three doses of flu, several unspeakable paintings and the word toilet which seemed to contaminate our entire household. Suddenly children who had hitherto slipped off discreetly to the lavatory were asking “C-ny-go toilet, Dad?” My wife was in despair and in no mood to listen to my complaint that I didn’t much care for being called a dad either.

Dads are men in suits who spank Dennis the Menace over their knee. Dads have slippers, the evening paper and zero libido.

I had always encouraged our children to use my christian name. If it was good enough for God, then it was good enough for them. But one term in the plunge pool of mass culture that is St Jude’s and I was dad, the lavatory was a toilet and Tom was a Dirty Den soundalike.

After all that, lice hold little fear for us, Mr Bouncy.