They do this sometimes, pretend that we’re actually all friends. It’s like they can turn it on and off.

Dimi and Matt begin wrenching at the upturned legs of Mr Clark’s chair. I know exactly what they’re doing – it’s a prank I’ve fallen victim to three times over the course of this term.

‘Morcombe!’ Dimi snaps. ‘Clark’ll be back in a minute. Get hold of a leg.’

I do as I’m told. With Matt and me holding the chair as firmly as we can, Dimi leans all of his weight into one of the steel legs until it gives way. The tubing buckles and flattens where it meets the seat, sending flakes of paint jumping clear, and he folds the leg until it’s jutting out sideways. He bends it all the way back to where it started and then rocks it side to side until the metal is on the verge of snapping. With the leg robbed of all its strength, he sets it back to where it should be. The same technique is applied to the other three. Matt and Dimi laugh as we turn the chair the right way up and delicately steady it, ready for use. It’s only just able to stand upright unaided. Mr Clark’s generous frame free-falling into it is an image that it’s impossible not to be amused by.

The three of us distance ourselves from the scene of the crime. My eyes flit from Matt to Dimi as they take their seats. Alone with them, I’m exposed, at risk. I don’t trust this affable front of theirs. I’m about to sit down when it occurs to me to check that my own seat hasn’t been similarly booby-trapped. It’s solid. Matt crosses his legs on top of his desk and pulls out a pack of Wrigley’s Extra. He tosses one in the air and catches it in his mouth.

‘Over here!’ Dimi shouts and waits with his mouth agape. Matt launches one and Dimi crouches to catch it.

‘Open wide, Morcombe,’ Matt says.

‘I’m OK,’ I tell him.

‘What did I tell you about looking so scared all the time?’ Dimi says. ‘It’s a piece of chewing gum. Not gonna kill you.’

Matt is tossing the small white nugget in his palm. It could be anything. ‘Play the game, pal,’ he says. ‘Ready?’

I tip my head back and limply open my jaw. When it arrives, I let it bounce off my cheek and on to the floor.