‘I hoped I’d be able to make him see sense,’ I say, knowing how feeble it sounds in spite of being true.

‘I see conspiracies everywhere, that’s my trouble,’ says Sergeant Zailer. ‘What I don’t know is, who’s on the receiving end of this one: you? Me? One colossal piss-take—that’s what this sounds like to me.’

I feel as if I might pass out. There’s a sharp pain between my shoulder-blades. I picture myself pressing a big red button: stop. I imagine my finger holding the button down—it’s supposed to make the bad thoughts go into retreat. Whichever book said it worked was lying.

Conspiracies: they’re what I fear most. I was wrong before. My nightmare didn’t start when I went to London with Aidan. It started earlier, much earlier. The list of possible starting points is endless: when Mary Trelease walked into my life, when I met Him and Her, when I came into the world as Godfrey and Inge Bussey’s daughter.

Sergeant Zailer holds up her hands. ‘Don’t worry—if there’s any chance a crime’s been committed, I’ll do whatever it takes to bottom that out,’ she says. Her words are no comfort. Aidan and Mary Trelease, conspiring together against me. If it’s true, I don’t want to know. I couldn’t bear it. Is that where he’s been, all the nights he hasn’t been with me?

I stand up, wincing as my weight lands on my injured foot. ‘I made a mistake coming here. I’m sorry.’

‘Don’t be. Have a seat. If I’m going to take this forward, we need to sort out a proper statement . . .’

‘No! I don’t want to make a statement. I’ve changed my mind.’

‘Ruth, calm down.’

‘I know the law. You can’t force me to be a witness. I haven’t done anything wrong. You can’t arrest me—that means I can leave.’

I limp to the door, open it, hurry down the corridor as fast as I can, which isn’t very fast. Sergeant Zailer soon catches me up. She strolls alongside me, saying nothing as we pass reception and head out into cold air that’s like a slap in the face. She whistles and examines her long fingernails, as if our walking side by side is a coincidence. Eventually she says, conversationally, ‘Do you know what’s happening tomorrow night, Ruth?’

‘No.’

‘It’s my engagement party. You wouldn’t . . . this whole thing wouldn’t by any chance be related to that, would it? You aren’t going to pop out of a cake tomorrow night and say “Surprise!”, are you? And if you are, it wouldn’t be anything to do with a certain Colin Sellers, would it?’

I stop, turn to face her. ‘I don’t know who or what you’re talking about. Forget everything I said, all right?’ And then I start to run, properly run, grinding the pain further into my foot, and she doesn’t follow me. She shouts after me that she’ll be in touch. I pull open my car door, feeling her eyes burning into my back.