A fire door led to a fenced-off bit of space at the back, about half a house’s worth of original garden. There were small trees along the line of the terrace, and white garden umbrellas mushroomed over the larger part of the garden reserved for guests. The lit windows of the houses behind gave the space an intimate, tenement feel.

Becca’s plastic lighter glowed briefly, neon pink. It had been years since Robin had smoked, usually even the smell turned her stomach these days, but she felt a momentary yearning for the little ritual of it, the camaraderie.

‘Private investigators.’ Becca exhaled, shaking her head. ‘I mean, I knew she wouldn’t leave it but I thought she’d just keep badgering the police.’

‘She’s been really worried.’

‘Out of her mind, probably. I know. And I feel horrible – shitty. But I just couldn’t do it any more.’

Robin channelled Maggie, her gentle voice. ‘What was going on, Becca?’

‘Taz said you promised you wouldn’t tell her where I was.’

‘Yes, I did.’

She took a deep breath. ‘Mum relies on me,’ she said. ‘Relied.’ Her eyebrows flicked up. ‘Always has, since I was little.’

‘She said you’re very close.’

‘We are, I love her – I mean, she’s my mum. But I can’t …’ Fleeting expressions crossed her face, one then another, as if she were conducting a silent argument with herself. ‘This is what I can’t stand,’ she said. ‘The guilt. Constantly feeling like I’m not doing enough, like I should basically give up having any kind of life of my own. It probably still wouldn’t be enough if I did.’ She looked away.

‘Why do you feel guilty?’

‘My mum’s agoraphobic,’ she said. ‘Technically, I don’t even know if she is because she’s never actually seen anyone about it – she refuses. Either way, she’s a shut-in. She doesn’t go outside.’

‘Why?’

‘She’s scared.’

‘Of what? Did something happen to her?’

‘No. Or not that she’s ever told me. She’s just always been like it, as long as I can remember – petrified of the world and other people. When I was a kid, after Dad died, she didn’t have a choice, she had to interact to some extent. Just now and again, you know – one school event out of every two or three, just enough to stop people getting suspicious. If she hadn’t, someone would have noticed and I probably would have been taken away or something. Then she would have been totally on her own and she would have been stuffed.’

‘How so?’

‘She couldn’t even go shopping without me – I was doing the weekly shop on my own by the time I was ten. And as soon as I left school, that was it, overnight – she went into the house and hasn’t been out since. Like she’d been tortured and it was finally over.’