When you become a supply teacher, you join the ranks of the lowest of the low. If you’re lucky enough to enter a grammar school, the pupils’ disdain will be subtle - a quietly superior air, a condescending glance. But, in time, you will learn to tolerate this.

However, the nature of the job means that the roughest, toughest, meanest schools are those which are most in need of supply teachers. When you venture into such a school, you will feel the oppression.

Though greeted warmly by grateful deputies, you will be conscious of a bubbling cauldron only yards away - which you will hear at full volume as you enter the classroom.

Lower school pupils tumble in as you speed read an A4 sheet taped to the desk and pray that the books it mentions exist.

Unprepared novices have the added misery of trying to get the class settled and working within minutes of arrival. This cannot be done unless the cavalry, in the form of a respected (and hopefully feared) regular starts the lesson. As long as all problems are sorted out before he or she leaves, success is possible.

Of course, there are always individuals who only remember they have no book, pen or pencil after this teacher has left, and the bedraggled “lates” who amble in with less equipment than a toddler at nursery.

Once the class is “working”, the role of the supply teacher becomes that of policeman. You parade, hands behind back, slowly around the room, trying not to look at the clock.

But you are soon fully occupied. Myriad events occur simultaneously: a pupil teeters perilously back on a chair; another sings in a high-pitched squeal; another snatches someone else’s pen; others chorus: “Miss, I don’t know what to do!” Patience sorely tested, you whirl around spitting venom, then spin again, smiling, to help the two exemplary pupils who do know how to ask for assistance. There is no respite because you lack the feared respect awarded only to a regular with clout.

Upper school classes are different. They pile in morose and unfriendly. The noise is less and they don’t want help. They don’t want anything. They want to be left alone. They start sullenly and continue for about half the lesson. Then there is a general tiredness, a feeling of “I’ve done enough now, I deserve a break”. The questions start: “Do we have to do all this? We don’t do all this writing when Mr X is here.” “Are you a real teacher?” One pupil chats with another. The holiday camp ethos spreads. The teacher’s main task becomes suppression: “Sit down, sit down now!” “If you haven’t enough work, I’ll give you more!” “What o you think you’re doing?” “You don’t leave your place without my permission.”

Once you find yourself saying this it’s a lost cause, it’s best to go for the all-out shout. There’s the risk of absolute humiliation - but if school discipline isn’t too far gone and you’ve still got that smouldering teacher anger, you might get away with it.

One other point: you must make your voice as deep as possible. A high-pitched squeak will be received with derision. If the blast achieves silence, you then pick a victim, anyone who emits a noise, and send them out - ideally to an effective isolation unit.

Now your credibility has been established, you get a modicum of respect. There will be an undercurrent of “uh, uh, she means business”, and you suddenly become more dangerous.

Unless, that is, you choose the wrong victim. If you pick one of the “I’ve been sent out so many times I make a career of it,” you’re in trouble. He’ll make a smart Alec comment or swear as he flounces off saying he’s going home. The only face saver is to act cool, give a subtle shrug and be polite and helpful in an “I’m making sure the rest of you get down to work way”. Firm but fair.

Then you can make sure the so-and-so doesn’t get away with it. A phone call to a prominent (and fierce) staff member, audible to the class, is best - with a confident line such as: “So, if you wouldn’t mind just picking him up.” The best hope of survival in a secondary school is to do one of three things:

* Attach yourself to prim, highly-disciplined schools - but risk poverty.

* Stick to one tough school as this improves your chances of falling for fewer scams, or at least knowing the names of the culprits.

* Learn some lateral thinking puzzles. Maybe in art or tech lessons, one can sometimes get pupils to continue with their regular work, especially if the supply teacher has some knowledge of the subject. But lessons such as science (and I am a science teacher) can be excruciating when the children recognise their rubbishy “fill in” status.

It’s best to call a halt halfway through (when there is still work going on to be halted) and do some puzzles. Why? Because when you tell a story, using a bit of the old anger to get quiet, then challenge them to find the answer, the adrenaline starts flowing and the kids are hooked and interested. And when you next meet the class, there is an increased chance that they will work and behave a bit better with the promise of “some puzzles if there’s a fair amount of work done first.”

Recommended Lateral thinking books:‘Lateral Thinking Puzzlers’ by Paul Sloane (Sterling Publishing, New York 1992)‘Perplexing Lateral Thinking Puzzles’, by Paul Sloane and Des MacHale (Sterling Publishing, 1997)