They have been discussing some of the more eccentric school rules that they are often called upon to enforce, many of which they find impossible to implement.

One teacher was expected to stop laughter in classrooms at all times.

But one contributor claimed an even less practical rule: “No black underwear to be worn. How could they check?”

Sartorial conformity is a particularly widespread concern. One school banned “provocative” hairstyles, while another coloured socks.

Another teacher says that her school insists that boys and girls maintain a three-foot distance between each other at all times.

And prurience does not stop in the classroom. One teacher said her school prohibited dating between pupils, at all times. “One of my students got punished and sent to the school counsellor last month for being caught holding hands with a boy while wearing school uniform.”

But, while many teachers bemoan hours spent enforcing the unenforceable, others find that certain rules can bring a frisson of satisfaction. Listing unusual school rules, one contributor wrote: “Having to stand whenever a teacher entered the room. I like that one.”