She doesn’t respond. Part of me wants to tell her I’m worried I’m losing my son. For so many years we’ve been so close, more like friends than mother and child. I’ve encouraged him in his art, taken him out sketching. He’s always turned to me when he’s been upset, as much as he has to Hugh. He’s always told me everything. So why does he now feel that he has to suffer alone?

‘He keeps asking if they’ve caught anyone yet.’

‘It’s understandable,’ she says. ‘He’s young. He’s lost an aunt.’

I hesitate. She’d known, surely?

‘You know Kate was Connor’s mother?’

She nods.

‘How much did she tell you?’

‘Everything, I think. I know you took Connor when he was a baby.’

There’s a tightening in my throat, a defensiveness. It’s that word. ‘Took’. I feel the same familiar spasm of irritation – the rewritten story, the buried truth – and I try to swallow it down.

‘We didn’t take him, exactly. Back then, Kate wanted us to have him.’

Even if she didn’t later, I think. I wonder what Kate’s version of the story became. I imagine she told her friends that we’d swooped in, that we snatched Connor when she was managing perfectly well, that we only wanted her baby because we couldn’t have one of our own.

Again the tiny part of me that’s relieved she’s gone bubbles up. I can’t help it, even though it makes me feel wretched. Connor is mine.

‘It was complicated. I loved her. But Kate could have a very distorted sense of how well she was coping.’

Anna smiles, as if to reassure me. I go on. ‘I know it wasn’t easy for her. Giving him up, I mean. She was very young, when he was born. Just a child herself, really. Sixteen. Only a little bit older than Connor is now.’

I look down at my coffee cup. I remember the day Connor was born. It had only been a few months since I got back from Berlin, and I’d been at a meeting. I was back in the programme, and I was glad. Things were going well. When I got home Hugh had packed an overnight bag. ‘Where are we going?’ I said, and he told me. Kate was in hospital. In labour. ‘I’ve called your father,’ he added. ‘But he isn’t answering.’

I couldn’t process what I was hearing, yet at the same time part of me knew it was true.

‘In labour?’ I said. ‘But—?’

‘That’s what they said.’

But she’s sixteen, I wanted to say. She has no job. She’s living at home, our father is supposed to be looking after her.

‘She can’t be.’

‘Well, apparently she is. We need to go.’

By the time we arrived Connor had been born. ‘Don’t be angry,’ said Hugh, before we went in. ‘She needs our support.’

She was sitting in bed, holding him. She passed him to me as soon as I walked in, and the love I felt for him was instant and shocking in its intensity. I couldn’t have been angry with her, even if I’d wanted to.

‘He’s beautiful,’ I said. Kate closed her eyes, suddenly exhausted, then looked away.

Later, we talked about what had happened. She claimed she hadn’t even known she was pregnant. Hugh said it wasn’t that uncommon. ‘Particularly with teenage girls,’ he said. ‘Their hormones might not have stabilized, so their periods can be irregular anyway. It’s surprising, perhaps, but it does happen.’ I tried to imagine it. It was possible, I suppose; Kate was a plump child, faced with a body that was now unfamiliar. She might have missed the fact she was carrying a baby.

‘She tried to manage,’ I say to Anna now. ‘For a couple of years. But …’

I shrug. She had nothing. By the time Connor was three she’d taken him to Bristol – without telling anyone why – and was living in a tiny bedsit with a shared bathroom and no kitchen. She had an electric hob plugged in next to the sink and there was a travel kettle balanced on an upturned washing-up bowl. The only time I visited, the place smelt of urine and soiled nappies, and Kate was in bed while her son sat strapped into a car seat on the floor, naked and hungry.

I look up at Anna. ‘She asked me to take him. Just for a few months. Until she got on her feet. She loved Connor but couldn’t look after him. Mum wasn’t around, of course, and Dad had no interest. Six months turned into a year, and then two. You know how it is. Connor needed some stability. When he was about five we decided – all of us – that it’d be better if we formally adopted him.’

She nods. ‘You didn’t try to contact the father?’

‘It was all a bit of a mess. Kate never told us who he was.’ There’s a pause. I feel a sense of great shame, on Kate’s behalf, plus sadness for Connor. ‘I don’t think she really knew.’

‘Or maybe he wasn’t someone whose help she wanted …’

‘No.’ I look out of the window at the traffic, the taxis, the bikes wheeling by. The atmosphere is heavy. I want to brighten it. ‘But he has Hugh, now. They’re incredibly close. They’re actually very similar.’

I say it in a kind of rush. It’s ironic, I think. Hugh is the one person that Connor has no blood relationship to, yet it’s Hugh who Connor looks up to.

‘You know,’ says Anna, ‘Kate always told me that although it was very painful she was relieved when you offered to look after Connor. She said that, in a way, you saved her life.’

I wonder if she’s just trying to make me feel better. ‘She said that?’

‘Yes. She said if it hadn’t been for you and Hugh she’d have had to move back in with your father …’

She rolls her eyes, she thinks it’s a joke. I keep quiet. I’m not sure I’m ready to let her into the family story. Not that far, not yet. She senses my discomfort and reaches across the table to take my hand.

‘Kate loved you, you know?’

I feel a flush of relief, but then it’s replaced with a sadness so profound it’s physical, a beat within me. I look at my hand, in Anna’s, and think of the way I’d held Kate’s in mine. When she was a baby I’d take each tiny finger and marvel at its delicacy, its perfection. She was born early, so fragile, and yet so full of energy and desire for life. I wasn’t yet seven, but already my love for my sister was fierce.

And yet it wasn’t enough to save her.

‘She said that?’

Anna nods. ‘Often.’

‘I wish she’d told me that when she was alive. But then I guess she wouldn’t, would she?’

She smiles. ‘Nope …’ she says, laughing. ‘Never. That wouldn’t have been her style.’

We finish our drinks then take the Métro as far as Rue Saint-Maur. We walk to Anna’s apartment. She lives in a mansion block, above a laundrette. There’s a communal door and Anna tries the handle before punching the code into the entry lock. ‘It’s broken, half the time,’ she says. We go up to the first floor. There’s a writing desk on the landing, littered with post, and she pulls out one of its drawers and feels underneath it. ‘There’s a spare key here,’ she says. ‘It was Kate’s idea. She was always forgetting her keys. It’s handy for my boyfriend, too, if he gets here before me.’

So, there’s a boyfriend, I think, but I don’t ask questions. As with any new friendship, these are the details I’ll discover gradually. We go in, and she takes my bag, dropping it by the door. ‘You’re sure you won’t stay here?’ she says, but I tell her it’s fine, I’ll stay at the hotel I’ve booked, a few streets away. We’ve talked about it; I’d be in Kate’s room, surrounded by her things. It’s too early. ‘We’ll have a drink, then you can check in on the way to dinner. I know a great place. Anyway, come through …’

It’s a nice flat, big, with high ceilings and windows to the floor. The furniture in the living room is tasteful, if bland. There are framed posters on the walls, the Folies Bergère, the Chat Noir; the prints anyone might pick in a hurry. It hasn’t been decorated with love.

‘You rent this place?’ She nods. ‘It’s very nice.’

‘It’ll do for a while. Would you like a drink? Some wine? Or I might have beer.’

So there are some things Kate hasn’t told her. ‘Do you have any juice? Or some water?’