Then, suddenly, I had to acknowledge the existence of very small children and know about their curriculum. I quickly found that reading stories or doing science experiments with them is extremely pleasurable, with the added bonus - for a head - of not having to teach them all day. Until Miss Smith, in reception class 1, is away.

You stare at the message in disbelief. Miss Smith is never ill. That’s one of the reasons you put her in reception class 1. Your supply agencies are suffering the flu season, and they’ve already sent their remaining Australians to every school except yours. Your part-timers aren’t available either. You realise you’ll be teaching class 1 yourself, and you hurry to the staffroom for the keys.

They’re not on the hook. You grab an older child from the playground and tell him to find the premises officer for the spare set. Then you hunt for the register and money tin, and go to meet your charges like a shell-shocked soldier.

They’re lined up, eager, and they look at you with interest. So do their mothers. “You’ll have to be good today,” says one to her tiny daughter. “You’ve got Mr Kent.” It’s a friendly Monday morning joke, but the child bursts into tears.

I get the children through the door and they hang their coats up. Thomas shrieks. While trying to get his coat over his head, his zipper has jammed. I comfort him, the door is opened, and somehow we all reach the carpet.

Monday dinner money is a nightmare. It’s combined with money for film club, biscuits, books, raffle tickets. Sensible parents - how I love them - have put it all in an envelope, labelled appropriately. Other children clutch several coins and haven’t a clue how much they’ve got, or what it’s for. Andrew has 2p and tells me it’s for everything. The door opens and Samantha’s mum appears, with Samantha in tow. Sorry they’re late, but they had a bit of trouble, and how much does she owe fromthree weeks ago?

I abandon the register and make a list of who’s paid what, dispatching it upstairs in the care of two children I consider reliable. Moments later, the tin clatters down the stairs. Javed says: “Miss never sends Alan. He drops things.”

The children are fidgeting on the carpet now and one of them breaks wind loudly. I wonder how on earth Miss Smith manages to do her Monday money-gathering so efficiently. It’s a skill I’ve never fully appreciated.

I decide to read a story. I’m good at that, and it will occupy us for a while. I select a book and Troy raises his leg, shouting my name urgently. I look at him in panic. “I’ve got no shoes on, Miss,” he says, gender recognition not featuring largely in his life so far. Then Simone pipes up:

“You know what? Not this Saturday or next Saturday but the next Saturday after that, it’s my birthday.” I tell her I’m pleased, but just now we’re having a story. “I’ve heard that one,” says Omari. Well, that’s nice, I suggest, but possibly others in the class haven’t. “Yes we have,” they chorus. I select another. “We’ve had that too,” Omari says.

“I know,” I say brightly, hunting for something within their experience, “we’ll draw pictures of Miss Smith, and we’ll each think of something we can write about her.” The idea appeals and they settle in their seats. Fifteen seconds later they’ve finished their pictures. I look at the clock. God, another hour before we even hit playtime.

Suddenly, the door opens and the secretary brings in someone I’ve never seen before. “A supply teacher,” she says. “The new agency had one.” I greet her with jubilation, and in a moment she’s gathered the children, taken artefacts from her bag and launched into a lesson. When I return in half an hour, the class is happy and attentive.

Perhaps our current obsession with targets, performance management, and thresholds puts us in danger of forgetting the skills of young teachers such as Miss Smith, who, thank heavens, can cope with the form-filling but still see the real wood for the trees.

Mike Kent is head of Comber Grove primary, Camberwell, south London. Email: mikejkent@msn.com