Alix registers this uptick in the already strange narrative of Josie’s relationship with Walter. ‘So,’ she begins gently. ‘Josie. I’d love to hear more about this, but only if you’re comfortable talking about it. Remember, anything you’re not happy about can be deleted before this goes out.’

Josie nods her assent.

‘So, Walter was married? When you met him?’

There is a tiny pulse of silence, long enough for Alix to read Josie’s discomfort with the answer she is about to provide.

‘Yes,’ she says. ‘He was. But obviously I didn’t know. Obviously he didn’t tell me. Otherwise, I never would have got together with him. I mean, of course I wouldn’t.’

‘So, hold on. After that day, your fifteenth birthday, when he took you to the pub, how long was it before you found out that he was married?’

This time the silence is even longer. ‘Quite a long time,’ she says eventually. ‘I’d say a few years.’

‘A few years?’

‘Yes. I didn’t find out he was married until I was eighteen.’

‘So he was still living with her? Right up until then?’

‘No. He wasn’t. That’s why I didn’t know. Because he had his flat in London, that he had from his dad. But his ex and the boys lived outside London, somewhere in Essex. He went home at the weekends. It was all – it was a bit messy, I suppose.’

Alix nods but stays silent.

It’s raining when their session ends a while later and Alix offers to drive Josie home. After she drops her back, Alix watches from her car as she walks round the corner, to see which house she goes into. Alix knows this road. She’s been down it a thousand times: an unprepossessing rat run connecting Paddington with Kilburn. And there, just as Josie had described, a long sweep of huge Victorian villas in semi-detached pairs, all built close to the pavement and shabby and faded with no trees to protect them from the dirty fumes. She watches Josie unlock the door of a house set right behind a bus stop. She sees Walter in the window and is taken aback once more by how old he looks. She tries to imagine the handsome forty-two-year-old Josie had described kissing her in a pub when she was a girl, but it’s hard to do. He has not worn the passage of time well. She sees him turn as Josie enters the room and a small smile break over his face. He mouths something at her and then turns back to his laptop. Josie appears briefly by the window, holding her dog and looking behind her, before disappearing again. There is another window next to the bay in which Walter is sitting. This one has denim curtains which are half opened. Alix can see the shape of a wardrobe and a door. Somewhere beyond that door, she supposes, is Erin, the older girl, the one who still lives at home, the one who had her arm broken by the little sister who left home when she was sixteen.

And then a bus pulls up in front of the house and snaps Alix out of her peculiar reverie. She puts her car into gear and drives home.

At the kitchen counter she opens her laptop and googles Josie’s address. She adds the name ‘Walter Fair’ but nothing comes up. She adds the names ‘Josie Fair’, ‘Erin Fair’ and ‘Roxy Fair’, but still nothing comes up. As she’d suspected. Anonymous, like 90 per cent of the population of the world. Even in these days of ubiquitous sticky fingerprints all over social media, most people aren’t traceable on the internet. She puts the address into Google Maps and stares at the Street View for a while, scrolling up and down Josie’s road, looking for something, she’s not sure what.

Thursday, 4 July

Josie puts her denim jacket on over her T-shirt and joggers and looks at herself in the mirror. It’s the same denim jacket she’s had since she was a teenager, the one she was wearing on her fifteenth birthday in the pub with Walter. It’s worn on the elbows and at the cuffs, but she has kept it in one piece over the years, kept it looking smart enough to wear. It’s her lucky jacket, the jacket she was wearing when her life turned around, when she went from being the sort of girl who drank warm cider with rough boys to the sort of girl who had the love of a real man, who had beautiful babies and a two-bedroom flat. But that girl … that girl is starting to feel like a shapeshifter, a fraud, a one-dimensional paper doll. She’s blurring in her mind’s eye into a human puddle. She rips the jacket off and looks at herself again. She has kept her figure, somehow, without trying. She looks nice. She could probably wear similar clothes to Alix and look good in them. She flicks through her wardrobe, looking for something that’s not denim – why does she have so much denim? – and something that’s not grey. She finds a floaty black shirt that she’d bought to cover up her swimsuit once when it was really hot in the Lake District. She puts it on over her T-shirt and joggers and turns this way and the other. She decides she looks nice and she hangs her denim jacket back in the wardrobe. She gets some sunglasses out of her chest of drawers and tucks them into her hair and then she takes out her dangling turquoise earrings and replaces them with a pair of hoop earrings Walter had bought her for her birthday one year.

Walter glances at her as she gets the dog ready for his walk.

‘You look like you’re on holiday.’

‘Do I?’

‘Yes. You do.’

‘Well, it’s nice out. Thought I might hang out in the park for a bit. Get some ice cream.’

Walter looks out the window and then back at her. He says, ‘You know what, that sounds nice. I’ll come with you.’

Josie reels slightly. ‘Oh,’ she says. ‘No. I mean, I’m meeting my friend there. The school mum. You know.’

Walter narrows his eyes at her. ‘Are you sure it’s not a school dad you’re meeting?’ He has a playful tone to his voice, but she knows that beneath it there is a thin blade of anger.

She matches his playful tone and says, ‘God, Walter, you clearly never saw any of the school dads for you even to say that!’

He nods slowly and then puts his glasses back on and turns back to his screen. ‘Well,’ he says, ‘have fun. See you soon.’

She clips the dog’s lead on to his collar and leaves the flat.

‘Oh!’ says Alix, eyeing Josie up and down on her doorstep fifteen minutes later. ‘No denim!’

‘No,’ Josie replies brightly. ‘Not today. I wasn’t in the mood.’