I’ve been off sick all week. The culprit was the romantic Vietnamese meal for two that Graham Love cooked to celebrate his book deal. I say cook, but it was more re-heat. That’s right, the man I’d fallen for treated me to microwaved takeaway noodles that had probably been in his fridge for the best part of a month.

Within minutes of my return, Nigel Horsmel, the deputy head, has allocated me a cover class. Judith Crock’s. It’s the second half of a double lesson on life skills and it’s my punishment. There is nothing fair or arbitrary about the allocation of cover. If you go sick, Horsmel will take his revenge by finding you the worst lesson available for your first free period.

As I relieve Les Twigg, a lifer at St Brian’s who has long since given up on behaviour management, he surreptitiously offers me a paper knife - “just in case”. I politely decline, a decision I begin to regret as I look around the room. Horsmel’s really done me over this time. It’s a Year 10 class and the discussion theme is “The myths of masturbation”. A lad at the back known as Spam (no one can remember his real name) is explaining loudly why it’s nothing to be ashamed of and offers himself as a classroom resource.

“Just say the word, Miss. I’m not embarrassed,” he says, and I believe him.

Spam’s kinaesthetic learning experiences are notorious at St Brian’s. His mother says he’s just never been very keen on clothes.

I try to ignore the growing chaos, but the class just gets noisier and more lewd. Then, to my horror, I realise that Ramona Lynch is in the room. The star of Orlando Jones’s party-cum-orgy. “Do you know where your G spot is, Miss?” she shouts as the atmosphere nears hysteria. “One thing I do know, Ramona, is that you’re in Year 12. Why are you here?” “I’m on the peer mentoring scheme, that’s why. Helping this lot stay sorted. OK?”

As the bell goes Ramona gives me a knowing smile. I flash back to last Monday night at Graham’s flat. His romantic writer’s turret turned out to be a freezing squat with half a dozen other residents: stoned South Africans sprawled around a kitchen table piled high with Pizza Pronto boxes.

Graham spent the whole of our “meal” on his mobile screaming at his publisher. Slightly drunk, I eventually snatched the phone from him and said I’d have a word. The line was dead. I suddenly realised there was no book, no publisher. I felt humiliated and scared.

Graham briefly nodded off and I pulled out my mobile. Brenda Gache had sent me a text message as we were leaving the pub but I hadn’t had time to read it. I opened the message and just managed to see the words “Graham” and “mad” before he woke up and said he had something to show me.

He left the room and returned with some photographs. “There,” he said triumphantly. “For my book cover. I’m designing it myself.” The pictures were of Graham and Ramona Lynch holding hands. I called a cab.

I watch Ramona shimmy out of the door just as Graham walks in doing an exaggerated mime of a paparazzi photographer as he passes her. “Fancy a spot of satay, Charity?” he asks cheerfully. I pack my books into my plastic boxes and concentrate on not crying. What a fool I’ve been. “Afraid not, Graham, it’s the IT working party tonight.”

Next week: Blessed are the laptops