Mary taps me on the shoulder. ‘Wrong,’ she says. ‘If you want a unique selling point, how about this? You’re the only person who’s ever laid into them personally. You yelled at them, said some things that were pretty hard for them to take—probably no one else has ever done that. It’s easy to forgive attacks when you yourself aren’t the victim. “Stephen and Gemma? No problem: all they did was nearly kill our daughter. Someone shouting at us and telling us we’re wrong about things? Sorry: unforgivable.” Do you see what I’m trying to say?’

I think I do. If I can bring myself to forgive Stephen and Gemma, I’ll be better than my parents, more Christian than they are, even though I’m not a Christian and don’t believe in God. Aidan, Mary, Stephen, Gemma, Mum, Dad, me. I can maybe forgive us all.

‘My point is,’ says Mary, ‘your parents are two great big stonking pieces of shit. Fuck them.’

I manage a weak smile. ‘Tell me about Aidan and Martha,’ I say.

Instantly, the gleam in Mary’s eyes starts to fade, as if she’s been cut off from her energy supply. ‘On one condition,’ she says. ‘This is my story, so I get to be judge, jury and executioner. If you’re tempted to exonerate anybody, do it in the privacy of your own head. I’m not as enlightened as you.’

I nod. Mary is freer than I am. She doesn’t worry about balancing the blame books. She takes her unhappiness and does what she wants with it. Could I be like her from now on, or will I always feel as if there’s some kind of external moral arbitrator watching every move I make, unseen and infallible?

Mary lights a cigarette. ‘Martha and Aidan met at a job interview. Fellow Commoner in Creative Arts, Trinity College, Cambridge. Aidan got it, Martha didn’t. She put a brave face on it, went on until everyone was sick to death of her about how she didn’t get it because she wasn’t common enough.’ She smiles. ‘We had a student teacher once who asked us how many television sets our families owned. Martha had the most: seven. The teacher was shocked. She was a bit of a luddite grow-your-own-vegetables type. She asked Martha what rooms the tellies were in, and Martha listed six: one of the lounges, the kitchen, her bedroom, her parents’ bedroom, her den, the summer house. The teacher was waiting to hear about the seventh, and Martha must have realised how it would sound, so she clammed up. The teacher asked her outright. Martha turned as red as a tomato, and had to admit that it was on the jet.’

‘A private jet?’