Even as I have come around to her way of thinking, however, she has come around to mine. ‘I just don’t see the harm in it,’ she says.

Agnes is tucked up in my bedroom. Hanna has slipped in beside her. The kitchen-diner’s large; there is a pull-out couch.

Click-clack.

I’m sitting up before I’m even awake.

Click-clack.

I know this sound. I swing myself off the couch, tensed against the slightest sound, a thump, a creak, as I lever my weight from the frame. Silence.

Click-clack.

It’s coming from the bedroom. A shutter sound. Christ. I take a knife from the magnetic strip on the wall and edge towards the door. I open it, lean round. The bedroom door is open. There is a figure at the window, a box raised to her face.

Click-clack.

‘Agnes.’

She turns. She motions, ‘Shh.’

I slip past the bed – Hanna is still sleeping – and up to the window. When they refurbished the building they put in soundproof glass. A fancy kind, and very effective. Below us, a car burns in silence. Kids are dancing round it to a music we cannot hear.

Click-clack.

This is her father’s camera, the bulky one he got the Christmas I stayed with them.

‘Go back to bed.’

‘I want to watch.’

‘Go on.’

‘Is that our car?’

‘Of course not.’

‘It could be.’

‘You’re parked on the other side of the building.’

‘Agnes?’ Hanna’s awake.

Agnes puts down the camera and climbs into bed, snuggling down with her mother.

‘Why are the curtains open?’

I draw them. ‘Goodnight.’

I sit a while with my phone, watching mash-ups, mapping feeds, behaving, in other words, much like every other concerned householder tonight. (The lights are on all over the estate.) The gossip feeds are buzzing, but it looks as though tonight’s action is headed west, away from us. Nothing happens. Nothing much. I see some young men wielding bats, crossing the square below my kitchen window. Vigilantes. Good. We look after our own in here, most of the time.

Agnes has settled back to sleep. I’m impressed. I would have thought the big bad city would have given her nightmares.

Their house is enclaved now. I was there last month, picking up Agnes for a date. (It was a kind of date. A meal, a show. It was fun. It was a glimpse of what the future Agnes ought to be like, unless her parents’ separation ruins things for her.)

I remember I drove up to the house and there was this flimsy plastic barricade across their road. Pointless. A strong gust of wind would rip it off. That or the bull-bars of a speeding 4by4. There was a gatehouse next to it, and a kid slumped there in the uniform, several sizes too big, of a D-list private security company.

‘How long’s this been here?’ I asked him, jovial enough. Breaking the ice.

‘Who was it you wanted?’

There were no special signs of decline there – nothing obvious to explain the barrier. Presumably there are more break-ins there now, but that’s true everywhere. The gate is best understood as a gesture – a community’s more or less neurotic response to the gathering general threat.

Anyway I parked up below the house. When I first came here the view of the mountains had impressed me into thinking I had fallen into a pocket of genuine countryside, but now I saw that the place was not so very different from the housing estate that had haunted my childhood. It was simply better located, more expansive, its gardens concealed behind high hedges, with lines of mature trees preserved here and there, to hint at woods long since cut down. How many children’s memories did this place erase, I wonder?

I sit up in bed again. Spring up, heart hammering.

It’s just after dawn – whatever magic there was has gone out of the air, but it’s still not properly light. I pad over to the light switch, shivering. It occurs to me that I am naked. Hanna could walk in. Agnes. And the kitchen blinds are open. Fuck it. Snap. And into bed again. Well, couch. Jesus, it’s cold.

It’s not the light has woken me, or the cold. It’s the estate. The memories it has not quite erased. That sound: Click-clack.

Was it Michel that night, watching me throw my mother away? Absurd. Taking photographs? No. This is the logic of nightmare – a welling paranoia that, given its head, could swallow everything and everyone.

But even as I’m rejecting the idea – the product of a troubled night, no more, a coincidence – I remember something else.

The riverbank. Michel’s ring of fridges. His redoubt. The voyage. ‘We’re sailing round the world.’ Hanna’s skin glowing. Michel’s lined and weathered face, in the low light of the living room, looking like something made out of wood.

Last year I told Bryon Vaux about my mother. He offered to help me find out about her. He walked me out of his office and Michel was there in the lobby waiting to talk to him. I hadn’t seen him in a while. ‘Conrad. Hi.’ He shook my hand. His skin was rough and broken. He was working with his hands.

I tug my jeans on and go through to the bedroom. Hanna and Agnes are awake, chatting.

‘Hanna. I think I know where he goes.’

So, after a gap of twenty years, I find myself going home, back to the town I grew up in.

The weather is getting worse by the hour. The rain comes down in sheets. The radio is a mess of flood warnings and contradictory travel advice. The traffic piles itself upon itself, and all three lanes set solid, trapping me in a tailback that streams up the hill in a red-grey blur. Emergency vehicles shoot past on the hard shoulder, lights showering the rain-mapped glass.

Another 4by4 goes by on the inside. Sod it. I turn the wheel.

The junction is jammed. Three hundred yards from the turn-off I join a line of cars waiting on the hard shoulder. Beside me, virtually the whole slow lane is signalling. It takes me twenty minutes to leave the motorway, and while I’m shunting and braking, the great lid of the sky begins to break up. Its uniform grey clumps into bricks and anvils that catch the late morning light. Sunlight floods the windscreen and the rain comes down harder than ever, the clouds wringing themselves out like rags.

It’s mid-afternoon by the time I find a way through the outskirts of town. I park up in a crescent of new houses.

The road into the centre is closed to traffic. I walk along its dotted white line. Even that paltry transgression – stepping where cars would normally run – feels strange to me. I wonder at myself and my own absurdity. I have spent too long in the city, obeying its tight rules of conduct, stepping out its precise, pedestrian dances.

Floodwaters have swept trash in piles against garden walls. Amongst the leaf-litter and twigs are fragments of man-made stuff. Smashed shelving, squares of plywood, lolly sticks, boxes, cartons, pallets. Crisp packets. Styrofoam. Someone is wrestling a sofa chair through their front door. The chair was white once, and from the state of the fabric – the dark line running just below the level of its arms – you can see how high the water came. The sofa falls out into the front garden. A man follows it out. His shirt is smothered in dirt. Perhaps the waters rose around him, too. I imagine him rooted to the spot, vanishing, inch by inch, under a cold, thin slurry.

He drags his sofa chair over and leans it against his garden wall. He kneels, gets his weight under it, and heaves it over the wall onto the pavement. He comes out through the garden gate and drags the chair towards a flatbed truck piled with swollen hardboard and peeling kitchen units. I go to help him.

He waves me away. ‘I wouldn’t, mate. Your clothes.’

So I stand there, watching him work.

Eventually I come to an area of standing water. It’s not deep. I wade through it. My feet are wet through anyway; it doesn’t make any difference. There are shops, and a woman in a headscarf is using a broom to sweep water the colour of chocolate out of her front door and onto the pavement. In the road is a pile of ruined stock. Cardboard boxes bursting with rice. Open boxes full of chocolate bars, leaves and toilet tissue. I catch the woman’s eye, and look away.