The christening. Neither of us wanted to go there. It was six weeks ago now, but it still hung between us like a stained sheet on a washing line.

‘We’ve had breakfast,’ I said quickly. ‘Twice.’

‘Course we did!’ she agreed brightly. ‘And you had dinner with Mum?’

Mum hadn’t told her, then. I made a split-second calculation: we’d be there in an hour. There was no need to guarantee it would be a disaster by forcing Sophie to pick a side. ‘Yeah. We went to this Italian up there on the left. I think you and Toby would love it. It’s romantic. Well, I imagine it’s romantic,’ I added, a drop of acid.

Sophie flushed – it’s one of the most charming things about my little sister, the way every emotion plasters itself across her face like it’s a billboard. She was feeling bad for me – bad for us – that she’d bucked birth order and found commitment first, while I was still acting like the slutty girl with a bad rep at the sixth form prom.

‘Talking of which,’ she said, ‘Toby and I really wanted to ask if you’d like to be my maid of honour.’ She smoothed her fringe out of her eyes and smiled nervously. My heart leapt upwards with uncomplicated happiness.

‘Of course,’ I said, reaching across the table and taking her hand, squeezing it in apology. Sometimes I hate myself, and it makes me mean was what I was trying to say, but all she felt was the blood being squashed in her veins. I would wonder back then if everyone had an internal life as dark as my own – was it better if they did, or better if they didn’t? The first meant I wasn’t alone, the second meant there was no hope for humanity. ‘I’d be honoured. Literally.’

‘Good!’ she said, her face lighting up. Her expression dimmed a little as, I imagine, she ran a silent film of the worst potential version of events through her head. I tapped my bowl of coffee.

‘This is the hard stuff for me now, I promise. You don’t need to fret about it.’

‘I know,’ she said, her smile a wobbly line. ‘Of course. I’m really glad you’re up for it.’

Sophie swung the car off the Westway and onto the backstreets of Shepherd’s Bush, her neat VW Polo never nudging its German nose above the 30mph limit. Being good wasn’t even a decision for her, just a fact. A few turns later she pulled up outside our parents’ house.

‘Did you bring anything?’ she asked.

Of course I hadn’t.

‘Don’t worry, I’ve got a bottle of rosé in the boot. It can be from both of us. I wonder if they invited Esther?’

‘Esther?’ I said. My voice sounded like broken glass.