Ah yes. The Christmas do - when fate punishes us for going to work. Why do we go? I can think of no good reason why anyone should do it. It is like pushing a sprig of holly up your nose. You are glad when it’s over.

For me it is an obligation, as keenly anticipated as a session in the dentist’s chair. Though of course it is the highlight of the year for Marion from business studies, who lets her hair down and has two puddings.

But is there anyone else who believes this is a social occasion? I don’t think so. It is an extension of work, but in different clothes. And that’s a problem in itself. Senior staff agonise over what to wear. What sort of image should they strive for? The lad-about-town in T shirt and jeans, a true man of the people? Or the casual designer suit of a successful careerist?

Whatever they choose, they will inevitably be the object of derision from their younger colleagues, to whom the event is hugely important. It persuades them they are all friends with an exciting social life. So they go out to eat boil-in-the-bag turkey and laugh at the deputy’s shoes, then leave Norman from the science department in a skip on the high street. They will talk about it for months. The simple pleasures of youth.

Mind you, the head also thinks it’s important. She also wants to persuade herself that she leads a happy ship of convivial bonhomie. Smiling indulgently, she might even buy the wine, just to say thank you. But on no account should the head ever attend in person. Whatever she does will be remembered - as will whatever any of her tipsy staff might say. Trust me, careers have been derailed after that unwise extra glass of cheap Spanish.

So, however much your colleagues urge you on, say nothing. They only encourage you to put your head on the block for the cheap thrill of hearing someone say the things they dare not. And heads never forget. If you don’t believe me, anticipate the faint smile as that amusing suggestion of an unhealthy relationship with farm animals is catalogued in the file marked “reference”.

The whole occasion is a nightmare with a fanned melon starter. But if you find yourself backed into a corner and you have to attend, a commonsense approach should ensure that you go home relatively unscathed.

First, prepare sensibly. Don’t be like Year 10. Do your homework. Never attend a venue where your Year 11 girls work in the evening. This is not brain surgery is it?

It is shocking for them to see how you all avoid sitting next to Ron from technology, the one with poor hygiene and the conversation to die from. The poor dears will be shocked by your collective lack of charity. They will also be shocked by the art teacher’s exotic range of unwise tattoos, revealed when she dances on the table to the bursar’s rendition of “Bohemian Rhapsody” at the karaoke. Oh, and avoid karaoke.

Also avoid venues already booked by staff from another school, especially the one on which you have just unloaded Psycho Dane, the Year 9 boy who ate the school gerbil. They will not be pleased to see you.

Another tip. It is always a good idea to drive to the venue. It is the perfect excuse for refusing drink and preserving your dignity. Be wary though of offering lifts home to the lubricated. That strange supply teacher whose name you don’t know will forget where he lives and have you driving around for ages in search of a familiar landmark, and a maths teacher will be sick on your handbrake.

Perhaps, in the end, the best policy is to say “no”. Firmly. Stay at home.

You may become a social pariah in the remoter parts of the staffroom but it is a small price to pay - and certainly preferable to sitting next to the head of French, who has only one topic of conversation: her dog.

I count myself among such curmudgeons, and with good reason. The last time I ventured out, in the teeth of a December gale, I spent the evening trapped in the corner at a table with three losers slagging me off in slurred drunken tones. I realised at that moment that there is more to life.

Let’s be honest. Would you in any other circumstance choose to spend time with this bunch of misfits and no-hopers? Of course not. It is only work that has brought you together. It is all you could possibly ever have in common.

And as the December rain lashes down, and an over-refreshed geography teacher threatens to assault the head, and the LSAs throw bread at the head of English, you will look around at the carnage that represents your professional life. And you will weep.

So when the bill does arrives and the arguments start and the manager calls for the police, try giving the name of that rival school. It has been done before. When Janet slaps Adrian for being clever with his hands under the table and Martin, the unassuming economics teacher, threatens to chin the waiter who put his thumb in his gravy, you may have no alternative.

You never know, this time it might just work.

Geoff Brookes is deputy head of a south Wales comprehensive