Everything they say about English teachers is true. Surprisingly, my outdoor activities skills leave a lot to be desired. “Well, at least I’m mentally agile,” I point out timidly. Supposedly, outdoor activities are all about proving that you can conquer your “inner fear” and “reach the limits of your personal endurance”. I actually think that means showing that you can beat a load of 11-year-olds, but I’m keeping quiet. You’ve got to wonder about people who prefer being vertical to horizontal.

So we’re up this mountain. The PE blokes have elbowed the kids out of the way, and charged off down the steepest slope, rolling their eyes at all the “pathetic wimps” who don’t fancy their chances along a sheer rock face and an iced-over waterfall. That leaves 28 kids. And me. I have three crying children attached to every limb. The PE blokes are too loaded down with things like radio equipment and ground-to-air missiles to worry about small details like Marmite sandwiches and having enough chocolate bars to persuade the kids down a cliff. So my Arctic survival rucksack is currently twice my body weight. And that’s a real achievement. “Twenty more steps and you can have a Mars Bar! Stop crying and I’ll let you listen to iwantafuckyermotha all the way home. Thirty more steps and I’ll tell you all about the last bloke I snogged.” That’s pushing the motivational techniques a bit to the outer realms of memory, but I’m getting desperate.

The PE blokes are a fluorescent speck in the distance. Suddenly, from the depths of my rucksack, I can hear a crackling sound. Once I’ve pushed past the extra jumpers, the first-aid kit and the sanitary towels, I find a radio.

“Come in, Charlie Delta Oscar 2.” Who the hell is Charlie Delta Oscar 2? I gingerly press a button. “Do you mean me?” “Charlie Delta Oscar 2, do you read me?” Read me? That’s stretching the boundaries of literacy, I feel. I haven’t got time for this. I press the button again. “Can you come up and help me? I’ve got 28 crying children who are cold and hungry and I think that one of them has broken a leg.” There’s a silence. “You’ve got to say over and out at the end of a message, Charlie Delta Oscar 2. Over and out.” “COME AND HELP ME NOW!” “We cannot respond until you say ‘over and out’. Over and out.” I chuck the radio down the ravine. Over and out.

It turns out that abseiling doesn’t have anything to do with cruising round on a yacht. It’s when you throw yourself off some rock with only a rope between you and the staffroom in the sky. The Year 7 group I’ve called HEL 7 look apprehensive. The PE blokes leap over with gay abandon. “What are you waiting for? Hurry up, we’re going jet-skiing in an hour. Look, it’s only a 1,000ft drop, you little wimps. Just throw them over, Gemma, they“ll soon get the hang of it.” HEL 7 start to cry. There’s a fluorescent mutter from further down. “Period pain. Typical.”

The PE blokes have been taking pastoral lessons from the SAS. We’ve spent most of the afternoon learning how to chuck balls at various living creatures, most notably those members of HEL 7 who couldn’t make it down the black ski slope in 30 seconds flat.

“They’ve got to learn, Gemma. It doesn’t hurt, really. I used to do it when I was their age, and nothing’s happened to me. Hit me. Go on, hit me, as hard as you like.” A queue silently forms. “Test us, challenge us to anything, go on.” Someone suggests breath-holding. We leave for a story as the PE blokes earnestly debate whether death by asphyxiation would mean winning or losing. You couldn’t exactly hold a re-match. It turns out that there are some sports we could learn to like. Blood sports. Me and HEL 7 are beginning to appreciate this endurance thing after all, but on a slightly more metaphorical level. And they say that English teachers are useless.

“How long, Miss?” Not long at all.

Gemma Warren teaches atThe Latymer School, Edmonton, north London.