‘Very posh them Salten House dinners, so I hear,’ Rick says. ‘My youngest does a bit of waitressing up there for pocket money, and I hear all sorts. Canopies, champagne, the works.’

‘I’ve never been to one before,’ Kate says. ‘But it’s fifteen years since our class graduated, and I thought this year might be the one to go to.’

Fifteen? For a minute I think she’s got the maths wrong, but then I realise. It’s seventeen years since we left, after GCSEs, but if we’d stayed on for sixth form, she’d be right. For the rest of our class it will be their fifteen-year anniversary.

We swing round the corner of the lane and I hold Freya tighter, my heart in my mouth, wishing I’d brought the car seat. It was stupid of me not to think of it.

‘You come down here much?’ Rick says to me in the mirror.

‘No,’ I say. ‘I – I haven’t been back for a while. You know what it’s like.’ I shift awkwardly in the seat, knowing I am gripping Freya too tight, but unable to loosen my hold. ‘It’s hard to find the time.’

‘Beautiful bit of the world,’ Rick throws back. ‘I can’t imagine living anywhere else meself, but I suppose it’s different if you wasn’t born and bred here. Where are your parents from?’

‘They are – were –’ I stumble, and I feel Kate’s supportive presence at my side and take a breath. ‘My father lives in Scotland now, but I grew up in London.’

We rattle over a cattle grid, and then the trees open up and we are out on the marsh.

And suddenly it’s there. The Reach. Wide and grey and speckled with reeds, the wind-rippled waters reflecting the lazy streaks of sun-bleached cloud above, and the whole thing is so bright and clear and wide that I feel a lump in my throat.

Kate is watching my face, and I see her smile.

‘Had you forgotten?’ she asks softly. I shake my head.

‘Never.’ But it’s not true – I had forgotten. I had forgotten what it was like. There is nothing, nowhere like the Reach. I have seen many rivers, crossed other estuaries. But none as beautiful as this, where the land and the sky and the sea bleed into one another, soaking each other, mingling and mixing until it’s hard to know which is which, where the clouds end and the water starts.

The road is dwindling down to a single lane, and then to a pebbled track, with grass between the tyre marks.

And then I see it – the Tide Mill; a black silhouette against the cloud-streaked water, even shabbier and more drunken than I remember. It’s not a building so much as a collection of driftwood thrown together by the winds, and looking as if it might be torn apart by them at any point. My heart lurches in my chest and the memories come unbidden, beating at the inside of my head with feathered wings.

Thea, swimming naked in the Reach in the sunset, her skin turned gold in the evening light, the long black shadows of the stunted trees cutting across the flame-coloured water and turning the Reach to tiger-striped glory.

Kate, hanging out of the Mill window on a winter’s morning, when the frost was thick on the inside of the glass and furring the reeds and bulrushes, throwing open her arms and roaring her white breath to the sky.

Fatima, lying out on the wooden jetty in her tiny bathing suit, her skin turned mahogany with the summer sun and a pair of giant sunglasses reflecting the flickering light off the waves as she basked in the heat.

And Luc – Luc – but here my heart contracts and I can’t go on.

We have come to a barred gate across the track.

‘Better stop here,’ Kate says to Rick. ‘We had a high tide last night and the ground up ahead is still soft.’

‘You sure?’ He turns to look over his shoulder. ‘I don’t mind giving it a whirl.’

‘No, we’ll walk.’ She reaches for the door handle, and holds out a tenner, but he waves it away.

‘Your money’s no good here, duck.’

‘But, Rick –’

‘But, Rick, nothing. Your dad was a good man, no matter what others in this place say, and you done well to stick it out here with the gossips. Pay me another day.’

Kate swallows, and I can see she is trying to speak, but can’t, and so I speak for her.

‘Thank you, Rick,’ I say. ‘But I want to pay. Please.’

And I hold out ten pounds of my own.

Rick hesitates, and I put it in the ashtray and get out of the car, holding Freya in my arms while Kate retrieves my bag and the buggy from the boot. At last, when Freya is safely strapped in, he nods.

‘All right. But listen, you ladies need a lift anywhere, you call me, understand? Day or night. I don’t like to think of you out here with no transport. That place,’ he jerks his head at the Mill, ‘is going to fall down one of these days, and if you need a ride somewhere, you don’t hesitate to call me, tenner or no tenner. Got it?’

‘Got it,’ I say, and I nod.

There is something comforting in the thought.

AFTER RICK DRIVES away, we look at each other, each unaccountably tongue-tied, feeling the hot sun beating down on the top of our heads. I want to ask Kate about the message, but something is stopping me.

Before I have made up my mind to speak, Kate turns and opens the gate, closing it behind us, as I make my way down towards the short wooden walkway that joins the Tide Mill to the shore.

The Mill itself sits on a little spit of sand, barely bigger than the building itself, which I suppose was once joined to the bank. At some point, when the Mill was being constructed, a narrow channel was dug away, severing the Mill from the land and funnelling the rising and falling tide past the water wheel that used to sit in the channel. The wheel is long gone, only a stump of blackened wood sticking out at right angles from the wall shows where it once stood, and in its place is the wooden walkway, bridging the ten feet of water that separates the Mill from the shore. Seventeen years ago I remember running across it, all four of us at once sometimes, but now I can’t quite believe we trusted our weight to it.

It is narrower than I remember, the slats salt-bleached and rotten in places, and no handrail has been installed in the years since I last saw it, but Kate starts across it fearlessly, carrying my bag. I take a deep breath, trying to ignore the images in my head (slats giving way, the pram falling into the salt water), and I follow, my heart in my throat as I bounce the wheels across the treacherous gaps, only exhaling when we reach the comparative safety of the other side.

The door is unlocked, as it always is, always was. Kate turns the handle and stands back, letting me pass – and I wheel Freya up the wooden step and inside.

It’s seven years since I last saw Kate, but I have not been back to Salten for more than twice that. For a moment it is like I have stepped back in time, and I am fifteen, the ramshackle beauty of the place washing over me for the first time. I see again the long, asymmetrical windows with their cracked panes, overlooking the estuary, the vaulted roof that goes up and up to the blackened beams above, the staircase drunkenly twisting around the space, hopping from landing to rickety landing, past the bedrooms, until it reaches the attic lodged high in the rafters. I see the smoke-blacked stove with its snaking pipe, and the low sofa with its broken springs, and most of all the paintings, paintings everywhere. Some I don’t recognise, they must be Kate’s, but intermingled are a hundred that are like old friends or half-remembered names.

There, above the rust-stained sink in a gilt frame is Kate as a baby, her face round with chub, her concentration fierce as she reaches for something just out of view.

There, hanging between the two long windows is the unfinished canvas of the Reach on a winter’s morning, crackling with frost, and a single heron swooping low above the water.

Beside the door that leads to the outside toilet is a water-colour of Thea, her features dissolving at the edges of the rough paper.

And over the desk I catch sight of a pencil sketch of me and Fatima, arms entwined in a makeshift hammock, laughing, laughing, like there is nothing to fear in all the world.

It’s like a thousand memories assault me all at once, each of them with clutching fingers pulling me back into the past – and then I hear a loud bark, and I look down to see Shadow, bounding up to me, a flurry of white and grey. I fend him off, patting his head as he butts it against my leg, but he is not part of the past, and the spell is broken.