The next level up was obviously the pub. An entire section of the house’s back wall had been removed and replaced with hydraulic jacks. Between them was wedged a walnut counter top from which drinks were served by a trio of young women in black and white check dresses and Mary Quant haircuts. At the other end of the garden the lower branches of the tree had been draped with batik cloth and elaborately woven carpets to form a number of small alcoves in which cast-off garden furniture provided seating. Between the two ends were half a dozen platforms set at varying heights, each festooned with plant pots and mismatched chairs. There was only a scattering of customers, mostly white, unremarkably dressed but strangely difficult to look at – as if resisting my gaze.

I heard a whistle – loud, piercing, like someone signalling a sheep dog.

‘Somebody wants your attention,’ said Lesley.

I followed her gaze to an alcove at the far end of the garden where a woman with hair extensions of silver and electric blue was waving us over. It was Effra Thames. Tall and elongated like a wicked Jamaican girl who’d got on the wrong side of Willy Wonka, she had a narrow face, a rosebud mouth and eyes that slanted up at the corners. When she was sure that she had our attention she stopped waving, leaned back in her white plastic chair and smiled.

The platforms were connected by planks of wood laid between them. There were no safety rails and the planks bent alarmingly when you stepped on them. Needless to say, we took our time making our way across.

Next to Effra sat a large black man with a serious face and strong jaw. He stood politely as we approached and held out his hand. He wore a scarlet frock coat with tails and white facing and gold braid over a black T-shirt tucked into the belt of his winter camouflage trousers.

‘My name is Oberon,’ he said. ‘And you must be the famous Constable Grant that I have heard so much about.’ His accent was pure London but deeper, slower, older.

I shook his hand. It was large, rough-skinned, and there was just a flash of something. Gunpowder I thought, maybe pine needles, shouting, fear, exultation. He turned his attention to Lesley.

‘And the equally famous Constable May,’ said Oberon, and instead of shaking her hand lifted it to his lips. Some people can get away with stuff like that. I looked at Effra, who rolled her eyes in sympathy.

Once Oberon released Lesley’s hand I introduced her to Effra Thames, goddess of the River Effra, Brixton Market and the Peckham branch of the Black Beauticians Society.

‘Sit with us,’ said Effra. ‘Have a drink.’