To top things off the dinner ladies are unhappy. Students have been using their mobile phones in the dining room. They don’t know who they are exactly, but they can show me tomorrow. Should they be confiscated? I refer to the school handbook for our policy on the use of mobile phones.

There it is, in black and white: “students who bring mobile phones into school should turn them off when they arrive and keep them locked in their locker until the end of the day.”

TUESDAY Today the dinner ladies threaten to confiscate mobile phones. Our students are not impressed. Apparently they need them “in case of an emergency”.

What emergency? The school office is efficient at taking and delivering messages. And anyway, they say, the headteacher has said that they can carry them around school. I think not, but am not prepared to have a row in cae they are right. Just because we have a written policy in a handbook doesn’t mean it is the current policy as practised on the ground - or in the dining room.

Wednesday A general reminder about the use of mobile phones is given to the whole school. Apparently students are now allowed to carry them around with them as their lockers may be broken into and their phones taken. And Kelly helpfully points out that Mrs Bolton’s phone went off in their lesson the other day - and she answered it.

Thursday Kelly is caught using her mobile phone in school. She claims not to have been using it, just sending a text message to her boyfriend.

She is given detention for next Thursday after school as it is too short notice for parental consent for this evening. Kelly helpfully suggests that she could do her detention today if I ring her Mum. I can borrow her mobile.

Friday I’m invigilating a Year 11 mock exam and notice that at least half a dozen students have their mobiles with them. Phone a friend?

Catherine Clark teaches at a girls’ grammar school in Kent