You could be anywhere ... We were drifting through the Aegean. A hacksaw drone rent the silence of the wine-dark seas. “If you look closely at those rocks, you will notice ...” The dread voice of the teacher-who- thinks-the-world-is-his-classroom. There he was in shorts and Baden Powell hat. He banged on and on - fossils, fish, philosophy. His kin scarpered port and starboard. The boat stopped. He didn’t. Grown men flung themselves overboard. Fishes went belly up. Non-swimmers hurled themselves into treacherous depths. Children plunged anywhere he wasn’t.

When we surfaced he was still haranguing the waves like Hitler. We swam for land. So did he. A child picked up a shell. The tot got clobbered with erudition. Then a bloke in a Sheffield United shirt threw the relentless pedant to the waves. “Just shut it!” We all cheered.

I thought I wasn’t that kind of teacher. Wrong. I can listen to myself for yonks. Others can’t. I find myself fascinating. Others don’t. I hold forth at the family table. They glaze over. I plough on. Then they’ve gone. Wife takes to the Dyson. Cat crawls through flap. Big daughter winks at sister. Then goes upstairs and rings her on the mobile pretending to be Billy, the phantom boyfriend. Little daughter scarpers.

They dread my enthusiasms. They secretly love rock’n‘roll but would rather sort the laundry than endure another sermon on Sam Phillips and the hillbilly tradition. They used to love soccer, but not if it means another exegesis on QPR’s flat back four.

Is this what it’s like for my pupils? They can’t jump overboard. “Don’t put your hand up 10 minutes before lunch!” said a desperate pupil. “We’ll never eat. He might go off on one!” I’ve caught Teacher’s Disease. Maybe I’ve had it for years. Maybe it’s terminal. Hey you! Are you following this?