I walk between the sisters. O is sour-faced. Not having the option of walking on her own legs must loom large for her, and Daphne is probably deliberately pushing her buttons. She manages to put the boot in even though she apparently thinks O is my colleague at the copy centre, the person who transfers VHS to DVD or something. Being with Daphne is like being in a time capsule. It’s almost tempting to send her around the schools to talk to kids about the old days.

Today Daphne stops after a hundred metres and leans on my arm.

‘I’ve not been sleeping well,’ she confides, almost in a whisper. ‘And I’m feeling very nervous. What if we are being watched? Perhaps we should just go back to the hotel.’

O spins her chair around. I notice that, perhaps goaded by Daphne’s remarks on fitness, she’s turned the motor off and is using her arms to propel herself. Her face is flushed.

I take Daphne’s arm. I can’t remember what it feels like not to be able to sleep. I am a little jealous. It occurs to me I could offer her ASMR, but O probably wouldn’t like that, and Daphne herself would probably mock me.

‘I think the therapy is working, though,’ Daphne says, now fully availing herself of my arm. ‘I get flashes of lucidity – watch out for that mongoose, dear – and at first I thought, no, I can’t bear this. Why drag it out? You know, when one is losing one’s mind, one finds oneself almost looking forward to the time when the burden of mind is gone and then one won’t know what’s happening any more. Because the worst thing really is the awareness of everything one is losing, particularly oneself. Is that your shop there?’

‘No, that’s a charity shop.’

‘Right. Terrible eyes. Did you know one of our Ukrainian ancestors was an Ashkenazi Jew? It’s a long story. The bad eyesight comes from him but also the brain power. Ha! The vanished brain power.’

‘Stick with the therapy,’ O says, breathing hard. ‘It can’t do any harm.’

‘Oh, but it can. The therapy keeps me awake. And gives me strange dreams. I know I’m dreaming but I can’t stop. Sometimes I noctambulate—’

O’s chair suddenly stops and she folds forward, coughing violently. I let go of Daphne and bend down to help her. She waves me away, still coughing, until tears start streaming down her face.

‘O! Are you all right? Do you need help?’

Suddenly I feel incredibly tender towards O. Her sister is formidable, even in dementia. I flash the thought that Daphne is sucking all of O’s oxygen.

‘It’s nothing,’ O croaks. ‘Sorry if I alarmed you.’

‘I would like a change of prescription,’ Daphne says, as though nothing’s happened. ‘But the colonel says you need to approve any changes.’