The Guilty Party. Mel McGrath

dee-lish,’ Anna says, accepting Bo’s top-up. ‘I can’t tell you how nice it is to be here. You know how much I adore Ralphie . . .’

      Making a show of not listening, Bo sticks his fingers in his ears and begins loudly singing, la la la. ‘No babies, diseases or unfortunate events.’

      Anna, who has already polished off her second glass, fakes a smile.

      ‘Let’s eat,’ says Bo.

      At the table is Anna’s home-made pâté which is, of course, delicious, because, though Anna herself rarely eats, she makes it her business to be an amazing cook. Even when we were students and all we cooked was beans on toast, Anna would always come up with some delectable little variation on the theme, a grating of cheese, a splash of Lea and Perrins, a sprinkle of mustard powder, a spoonful of treacle and a splash of lemon and then sit and watch us eat it.

      ‘So, mate, what’s the plan?’ Dex asks, tucking into his third slice of pâté. ‘There’s a farmer’s market at the weekend, apparently.’

      ‘Fossils. Wine. Walks. A small addition to the Big Black Book. Otherwise, there is no plan,’ Bo says.

      Anna spreads a cracker and lays it delicately on her plate. ‘You’re going on a date?’

      ‘Already arranged,’ Bo says, knocking back his second glass. He’s swiped right on a woman living in one of the villages in the south of the island. ‘Because why not? Let’s just say I’m field testing my app’s performance in rural areas.’

      Anna leans in, her eyes bright, and momentarily rests her head on Dex’s shoulder. ‘What about you, darling?’

      ‘I haven’t really thought about it,’ says Dex.

      Bo has helped himself to seconds, and with his mouth full says, ‘Between getting trashed and bouts of casual sex, I’m intending to go on some lovely walks with my friends. Only if you want, though. It’s all really chill. Tomorrow morning we could go over to the Weares. There are feral goats everywhere and the fossiling is good if you get the right day. There’s a climbing outfit down that way too, if anyone fancies it. You climb up this rock face and onto the top by the prison. It’s kind of cool.’

      ‘Oh God, all that lycra,’ says Dex, camply.

      The pâté finished, Anna brings over the chicken. Neither Bo nor I have much talent in the kitchen, Bo because he always eats out and me because there’s always someone else’s washing up in the sink at the flat in Tottenham and because, until a month ago, I was always broke. The supposedly legendary entrepreneurial millennial spirit somehow passed me by. Ambition too. Hence temporary teaching assistant. Great work when there is any but, like any line of work these days that doesn’t involve tech, finance or roasting artisan coffee, terrible pay.

      Bo has now opened a third bottle.

      ‘By the way, Casspot, you’re looking very hot. Is that a new outfit or have you done something to your hair?’

      ‘Both.’

      ‘Oh?’ Anna’s eyebrows rise.

      Dex leans over from the other side of the table and plants a kiss on my hair. ‘You got that promotion! Why didn’t you say?’ ‘Let’s drink to promotions,’ Bo says, raising his glass.

      The glasses clink prettily and for a moment silence falls and is then broken by the strangled screech of some nocturnal creature.

      Anna puts down her glass. ‘What the hell was that?’

      ‘The cry of the Mer-Chicken,’ jokes Bo.

      ‘We’re about to eat its mate and it’s very, very angry,’ says Dex.

      ‘Whoever heard of a Mer-Chicken anyway?’ Anna says.

      ‘Everyone on Portland?’ says Bo.

      ‘It sounded like a vixen to me,’ I say.

      ‘Mate, if you’re talking about that thing in the porch it’s a crap stone mermaid with eighties hair someone bought on sale in the local garden centre,’ says Dex. ‘Wooo, I’m scared.’

      ‘Obviously that’s not the real one,’ Bo says.

      ‘Oh, and could that be because there is no real one?’ Dex eye-rolls.

      ‘Portlanders say it’s a harbinger of death,’ Bo goes on.

      ‘Don’t be creepy, darling,’ says Anna, addressing herself to Bo and, wielding the carving knife and fork, in her practical way, adds, ‘The only chicken in this house is the one sitting on the table getting cold. Now, leg or breast?’

      Later, after another few glasses of wine, we are sitting over plates of Normandy apple tart Dex bought from the French bakery in Butler’s Wharf when I hear myself say, ‘Maybe we’re rather creepy?’

      There is a stillness around the table. If you really want to know the truth, the Big Black Book has given me a queasy feeling for years. After what happened at the festival, I don’t know any more. Somewhere along the line did we lose our moral compass?

      ‘Oh dear, Cassie’s in one of her dark moods.’ Dex wipes a paper napkin across his lips.

      ‘Where did that come from all of a sudden?’ says Bo.

      ‘I don’t know . . . just all the in-jokes, never bringing new people into the Group, the Big Black Book.’

      Let me tell you a little about the Big Black Book. It feels as though we summoned it into being a lifetime ago. All these years later it still seems like the product of a spell. But it came out of one ordinary evening, when we were celebrating Anna’s birthday in Pizza Express. I was the girl who ordered the Veneziana back then, not because I particularly liked it (raisins on a pizza, God no), but because they donated 50p to charity if you did. I see that now for what it was – a particularly self-defeating form of virtue signalling, a product of the feeling of inadequacy which shadowed me then. I still had only the skimpiest notion of why Anna, Bo and even Dex seemed to want to hang out with me. Now I know that they saw me as living in a parallel moral universe, one that was no better or worse than theirs, only different and, in their view, as charmingly quaint as a piece of the expensively retro furniture with which they decorated their newly purchased bank-of-mum-and-dad luxury apartments. Anna, who viewed anything edible as reason to engage in moral combat, ordered a salad niçoise with no dressing or dough balls. Naturally, the boys always ordered whatever they wanted, never imagining that anyone would be stupid enough to do otherwise.

      Bo had stumped up for a bottle of cava – this was when he was still a struggling IT entrepreneur – and we were raising a glass when Anna said, ‘For my birthday, I’d like everyone to tell us all a secret. Don’t you think it would be fun for us to know something about each other that nobody else does?’

      We decided it would.

      We met the following evening at Bo’s. As I recall, Dex told his secret first. At age fifteen he’d lost his virginity to his PE teacher called Jamie. It happened one night in the Sainsbury’s car park behind the school. In exchange for his secrecy, Jamie gave Dex a pass out of PE for the rest of the term. At the time Dex revealed his secret, he and I were still a couple, and no one thought to ask whether Jamie was a man or a woman. In retrospect this was, of course, a mistake.

      Bo admitted to dognapping the family lurcher, Grace, in whom his parents took more interest than they did in their children. He caught a train home from boarding school, picked up Grace and, without his parents’ knowledge, took her on the train first to London then to Leeds where, claiming to have found her wandering the street, he dropped her off at the nearest shelter. His parents spent months trying to track the dog down but never found her. His father withdrew from the world and his mother fell apart. A year or so after Grace’s disappearance the new owners got in touch with Bo to thank him for bringing the dog into their lives. They’d named her Joy. It still tickled Bo to think about it.

      Anna admitted to sleeping with a reality TV star. She and Bo were in the off phase