"You're having a laugh!" Fifteen-year-old Dan is struggling with the knife and fork arrangements at his leavers' dinner. Initially, the adults at the table chuckle politely, assuming he's fooling around. But he isn't joking.
The cutlery's a mystery to him; he can't eat with the fork in his left hand and the knife in his right. In the end, he settles for a less orthodox set-up (fork right, knife left), announcing that "this is how we do it in Plumstead". Funny or terrifying? Possibly the latter, when you add to the mix the fact that Dan recently became a father.
Then again, you can't expect all the students at an inner London comp to have the airs and graces of those at a Swiss finishing school. And even though some of the boys are scratching uncomfortably at their collars, the kids look superb tonight. The girls are as meticulously turned out as any of the high school prom queens they've seen in American teen movies.
Judging by some of their faces, the Woolwich tanning salons have just enjoyed their most profitable day of the year. But the end of year school prom is more than a frivolous ritual. It's a rite of passage.
Next to Dan, Sean shuffles impatiently in his seat. A 6ft 3in lad with anger management problems, he's waiting for the dancing to start. "I can't eat this," he grumbles, before devouring his chocolate pudding. As he eats, his eyes flit around the room, checking that nobody has witnessed him enjoying this "rank" (non-fast) food.
The dinner and dance takes place at Charlton Athletic Football Club. My school, Saint Paul's Academy, has close links with Charlton. One of the departing Year 11s plays for the club, and the kids sit their GCSEs here at the Valley - the facilities are that good. But this April evening, thoughts of exams are far away.
It's my first leavers' prom as a teacher, and a genuinely moving experience. I took over pastoral responsibility for a difficult Year 11 form last September. And I was scared. But after a few exhausting weeks of animal noises and attitude, we started to get on. By now, I'm quite attached to them. Tonight, I realise how much I'm going to miss them. Their words of kindness and thanks are nothing short of overwhelming.
As I understand it, with difficult kids, appreciation is often shown through what they don't do: they don't disrupt, they don't turn up late, they don't argue. But there's such warmth tonight that - sorry if this sounds nauseous - I know I have the best job in the world.
The night ends with teachers and students on the dancefloor together. It's the last song of the night - Show Me the Way to Amarillo - and since the head requested it, he's going for it. Six feet away, Casey-Ann from my form is bopping around in a red dress, laughing with friends; back in Year 9 she was in so much trouble she came within a whisker of permanent exclusion.
Perhaps that's why tonight is so special. Yes, it's a pat on the back for the students who've been excellent throughout their school careers. But the girl in the red dress is here too, and she wants to be. Just like Dan. In spite of complaining that there's no alcohol, regardless of the fact that the knife and fork were a challenge... Dan's welcome as well.
Joe Curtis teaches English at St Paul's Academy, London. The pupils' names have been changed. l Coming soon in The TES: our feature on the glam, the glory - and the cost - of the prom.