One of my favourite moments in teaching was a little trick I played on a first-year class. I was to show some slides of pupils doing various classroom activities at a school open afternoon and the class had requested a preview.

At the front of the class sat two identical twins. They were best friends and always chattering, smiling and doing things to slightly annoy their teachers. So I switched the slides of the twins doing a role-play with a photograph of two identical monkeys picking at each other’s hair. The timing and the commentary were spot on and the response was a huge roar of laughter. The twins, I am pleased to say, laughed the loudest.

There are few finer moments in teaching, or in life, than when a group of people laugh together. The key word is “together”, because laughter at someone else’s expense is, as one of the great philosophers put it, a clear failure of empathy. Honest humour should be victimless.

What you laugh at is, of course, psychologically revealing. Cruel humour which is designed to reinforce the joker’s self-perceived superiority is usually associated with those who feel threatened and undervalued.

A GSOH - good sense of humour - is essential in education. Just look at some of the cascade of initiatives and reforms which splash down on us. Humour is our escape. We don’t want to become a profession, like dentistry say, which is devoid of humour. In most classrooms, I argue, a little bit of fun should never be too far away.

And, besides, there is much to learn about language by sharing, and analysing, the odd joke or two. Humour may emanate from a play of words, an unexpected twist or the element of surprise. These are also the techniques of creative writers.

Many of the funniest jokes use language with considerable skill and economy. And some moments of humour don’t require language at all.

Which reminds me of a jape where I was at the receiving end. One January, I accompanied a group of pupils on a week-long skiing course in the Cairngorms. When I returned, my classroom appeared different from the way I had left it.

Everything had been turned upside down! Over a 100 photographs were upside down. All the maps, pupils’ work and classroom notices had been turned upside down. Even the globe hanging from the ceiling had, somehow, been turned upside down.

The Higher class, all working intently without making a sound, were the obvious culprits. I entered, gaped and then turned my head sideways to try and read the upside-down timetable on the wall. We all laughed. There are few finer sounds.

John Greenlees teaches geography.