‘When even Oliver Morcombe can’t keep a straight face, I know I’m having my chain yanked,’ he says. Again, the eruption of laughter is disproportionate to Mr Clark’s funniness. He begins a lap of the room, considering everyone in turn. ‘I’ll work it out,’ he says. ‘You need to be up very early in the morning to get one over on me. I was a student here once – I know all the tricks.’ He returns to his desk but remains standing. A few phones are discreetly raised. This is clearly a spectacle worth risking confiscation over. ‘Anyway, here’s the plan for this afternoon, lads,’ he says, starting to lower himself into his chair.

There are a number of nasal snorts round the room. Amit’s shoulder is vibrating against mine.

‘What is it?’ he shouts, bouncing back to full height. He glances at his crotch. ‘Flies done up – check.’ He looks at the soles of his shoes. ‘No trail of bog roll or dog shit – check. Come on, lads. What’s so goddamn funny?’

‘You really wanna know, sir?’ Dimi Kyrkos says. ‘Check the bottom drawer of your desk.’ He can’t quite maintain the deadpan delivery, his voice swooping upward as he finishes the sentence. A tear drops from Amit’s cheek and splatters next to me.

‘Right,’ Mr Clark says, ‘let’s see what you’ve laid on for me.’

His sixteen-stone mass wallops into the chair like a piledriver. For half a second, he’s motionless. The class doesn’t make a sound. He leans towards his bottom drawer. The chair leans with him, just a few centimetres to the right. He tries to balance himself. His seat rocks back to the left, a little further this time. He begins to sway like a pendulum. Each movement is greater and faster than the last. His expression is that of a man who’s been stitched up and knows it. He’s trying to grab on to something, but the movement has become an oscillation, his head almost stationary but his abdomen gyrating wildly. There’s a crunch as one leg leaves the chair and Mr Clark tilts backwards. He’s going down. He makes a final attempt to grab something solid, flailing an arm behind him for the flimsy shelf beneath the whiteboard. He succeeds only in wrenching it down with him, sending marker pens scattering. The final descent is pure free fall, his head and torso disappearing behind the desk like he’s plummeting through a trapdoor.

I laugh so hard that no noise comes out. Amit grabs his tight curled hair as if he’s in pain. Matt Alford drops to the floor and curls up like a foetus. Nate Mackie jumps on to Mr Clark’s desk and chants at him while he lies on the ground, pointing his finger at him in time with the words.