He’d made sure that the knife was hidden, and then he’d gone to the garden centre, with his crippling hangover, and bought a range of different plants. It seemed important that he make it look like a big project – like he’d decided to landscape the whole back garden. He spent a fortune, he tells her now, just to conceal the reason for planting that single fuchsia bush.

‘I kept thinking they were going to come for me,’ he says now. ‘When they interviewed each of us – all the guests from the party – I was sure I’d let something slip or that someone else’s account would point the finger in my direction. For weeks, I hardly slept, so sure they would find something – some trace of evidence that would link me to her death.’

In the end, the party saved him. After the number of people who had been present, trampling through the house, the place was a mess of fingerprints and forensics. The door-to-door questions, the trawling through differing accounts, never turned up the murder weapon or indeed the murderer himself.

Except for Anton.

‘I felt conflicted,’ Greg tells her now. ‘I knew it was wrong – an innocent man going to prison. But then I thought, Well, how innocent is he? His behaviour towards her was terrible. And he was fucking my wife!’ His indignation bursts through, then recedes. ‘Sorry,’ he tells her. ‘I’m sorry.’

He shakes his head. ‘For years, I thought it would be okay. That I had put it all behind me. That I was safe. But then when Anton came back, and I could see you obsessing all over again … I just wanted him to go away. To leave us in peace. I thought if I could just scare him away, but …’

His eyes come to rest on the knife sitting on the table between them.

‘Hilary,’ he says. ‘What are we going to do?’

Clouds are gathering overhead in thick, tight bunches. The sky has darkened, and in the garden now a chill wind blows. All traces of summer heat have fled. Autumn is finally here.

The camellia bush she has bought lies on its side in the grass, and Hilary kneels beside it, easing the root-ball from the plastic pot. Gently, she loosens the feathery roots from the potting earth they’re moulded to.

She thinks of all the seasons that have passed here. The summer evenings dining out on the patio. The winter days while the garden slept beneath a blanket of snow. And all the while it kept its secret concealed within the dark heavy earth.