The great glass wall of client reception disclosed a cinematic view of the City, stretching down to the glittering ribbon of the river and the stately dome of St Paul’s. On the South Bank the great blocks of culture faced the towers of commerce, the National Theatre hunkered down on the edge of the Thames, its grey concrete balconies camouflaged against the sky. I put on my overcoat and led Jessica past the ranks of black leather sofas and neatly stacked periodicals, and the fresh fruit and orchids quietly dying in their glass vessels.

The Japanese garden on client reception had one of the best views in the City. Old enemies appeared on the eastern horizon: Magic Circle law firms sitting in state by Moorgate. From the balcony you could see St Andrew’s Church, a tiny nub of conscience subsisting in the centre of the financial monoliths, so much older than the buildings that blocked it from the sunlight. The leaves of the weeping willow in the churchyard spilled over the wrought-iron railings on to the pavement. The roof garden itself was composed of large obsidian stones and elegant little shrubs arranged on a bed of white sand. The sand was raked into perfect parallel trenches, like a ploughed field in delicate miniature. A slate walkway paved the edges, and formed a bridge over a tiny stream that bubbled up through the rocks. The sky seemed huge so many floors above the skyline, with no other buildings hemming it in. It closed like the lid of a freezer over the cold city. I felt proud to have brought her up here, on top of my impressive building, above my kingdom.

I slid the door closed behind us, and heard the comforting click of the catch, sealing my working world inside like the body of a despot in a vast stone tomb. The wind was strong so high above the street, and carried a film of drizzle that coated the garden with a thin layer of cold moisture. She walked away from me, her heels sounding on the grey slate, and leant on the stainless-steel railings that separated the balcony from the empty air behind.

‘I know what you’re thinking, James. I’m not on the run from the Mafia or the police, and I don’t want money from you or help or anything else really except a couple of showers’ worth of hot water. You work during the day. I go out at night. You won’t even see me, if you don’t want to.’

‘I don’t know how you are placed financially, Jessica,’ I said, slipping into my professional idiom, ‘but it seems to me that you could easily budget for a hotel with a higher degree of anonymity than an old university buddy’s house.’

She sat on the metal bar that ran around the side of the balcony and put her feet against the large black boulder nearest the edge of the carefully raked white sand, dimpled from the raindrops. Behind her I could see the roof of a building the architects had never intended for public view. It was ten storeys down. I thought how best to guide her back from her perch without showing that it made me uncomfortable.