I met Lisa Ragozzi at a Caffè Nero near her work at Borough, and I was glad she’d chosen there, because it was cosy in an anonymous way, a constant flow of students with laptops, bewildered tourists looking at their guidebook maps upside down, and office workers whose main aim was not to interact with another human being for the thirty minutes of their break.

The first thing I saw was how pretty she was. She had rich dark hair touching the collar of her white shirt, and dark eyes, but her cheekbones were hollowed out and her legs thin and stick-like under her tights. ‘Nora?’ she faltered. A nervous woman. A woman someone had damaged, perhaps.

‘Hello, Lisa. Thank you for meeting me.’

She was too polite to look me over, but I’d caught the micro-tell in her expression – it can’t be her. So now she would believe it really was a friend I was asking for. Maybe she’d open up more. ‘Please, sit down.’

I took my silly tall glass of coffee and sat looking at her, a pocket of silence among the background noise that washed against the walls. ‘You must be thinking this is very strange.’

‘Not really.’ Her knuckles went white around her mint tea. No calories. ‘I’ve always wondered if he – where he ended up. I had a little look after you messaged. He’s married? That’s your friend?’

I should have realised she’d do that, look him up. ‘She’d go mad if she knew I talked to you. Totally in denial about it, you see.’ Meaning: Please don’t contact Suzi.

She was nodding. ‘Of course. I was that way myself for so long.’

‘Can you tell me about it?’

And she told me her story, staring into her cooling tea, while I drank down my mix of cream and sugar and felt ashamed. Lisa had starved herself to a saint-like purity. Maybe so a man wouldn’t want her again. Maybe to hide in plain sight. She told me how she’d met Nick in her first year at Nottingham University, when he was in his second. How immediately she’d been bowled over by his attentions, when all the other boys she’d met only wanted to have fumbling sex then never talk to her in public. Bruised from a term-long affair with a rugby player, she’d found kind, attentive Nick – short, neatly built, a pleasant rather than sexy face – a lifeline. ‘He took me to dinner! That was unheard of. I mean it was only Pizza Express, but still. I was so flattered. And he remembered everything I told him, the names of all my tutors, my childhood cat, all of that. Before I knew it, we were living together.’

‘In a student house?’