A catering turf war has broken out at St Brian’s. Mr Burger, school sponsor and principal employer of former pupils, is out and Cuisine du Jour is in.

It seems Mr Burger overstretched itself with plans to turn the school into a catering academy, a scheme that involved the closure of all non-vocational departments and the renaming of the school as St Jamie’s.

This was too much for Oriel Greer, our LEA adviser, who has suddenly discovered the educational benefits of good nutrition. (This might have something to do with the fact that Cuisine du Jour is part-owned by Greer and Greer Associates, an “education services specialist” that is scooping all the juicy local school contracts.) Mr Burger isn’t going without a fight. Nigel Horsmel, the deputy head, is a vociferous supporter of our sponsor, arguing that the behavioural problems associated with junk food are a price worth paying for the synergies and prestige that accrue from a tie-up with a blue-chip local brand. Jessie McNally, the lunchtime supervisor, also has a vested interest, as her role largely consists of disarming violently hyperactive teenagers.

On the morning of the changeover, the playground looks like something out of a spaghetti western: burger wrappers swirl in the breeze as the caretaker removes the giant burger logo from the front gates. The staff are already taking bets on how long the new caterers will last. The last time the LEA brought in a new chef he disappeared after a pick-up truck full of pig’s offal accidentally arrived at his house or, rather, was deposited in his front garden.

At lunchtime the staffroom is a sauna as the kettle works overtime to rehydrate an endless supply of Pot Noodles. Unusually, Mick the Aussie is not eating out of a plastic container. As he walks by with a plate of something aromatic and tempting, I ask him if it’s last night’s leftovers.

“Naw mate, it’s the special in the canteen: lamb shanks with Moroccan-style couscous.”

There is a stampede for the canteen. At the door, Jessie McNally attempts to halt the rush. “You don’t wanna eat that foreign muck,” she yells. “At least you know where you stand with oven chips!”

Inside the hall, it seems the kids are equally unimpressed. The Year 10 twins Gavin and Gareth Gunner are using the crepes as frisbees, and a fruit pavlova is about to be launched at the serving hatch when chef appears, meat cleaver in one hand and a glass of red wine in the other. He has tattoos all the way up his arms and swears obscenely in a broad Welsh accent.

The Gunners retreat with that gutter instinct that tells them they can’t win this one. Jessie McNally is both shocked and smitten.

Within a week the canteen has received a favourable review in the local paper and several middle-class foodies have attempted to book tables.

Horsmel’s antipathy to the new venture dissolves as he senses a business opportunity and commissions a new sign for the front gate: the St Brian’s Bistro.

At the 13 Horseshoes, chef is an instant celebrity. He’s already on the darts team and his pint is poured as he walks through the door. It’s a special man that can beat Jessie McNally at arm wrestling.

Charity Casement is the alter ego of a north London teacher. Next week: Summer madness