Memory swamped me, and I slapped at the side of the tub to stop it. I sat up. From outside a shout wedged through the window. ‘For what shall it profit a man if he gain the whole world but lose his own soul?’

You could set your clock by those Bible verses. I hated them, but it was one of the things I’d learned to endure in my first two weeks there.

With the diarist I’d fallen into a hole. At the School-house I had to step down into it. That first morning a woman came out to fetch me, took me to an empty bedroom. ‘You’re to dry out in here,’ she said. ‘Then the old Slapper will want a word.’ That was the first time I blessed my eyes on Sal. A gleam of shaved head and a wink of gold ear-drops. Elbows jutting.

My own breath knifed me into the pillow, coughing.

By the time Sal came back, night had fallen. Nothing showed in the doorframe but the lights of her eyes, her cigar. Black skin through a scarf of smoke.

I’ve lost her. I turned over, tried to scrabble back into sleep.

‘Oh, no. Up you get.’

‘I can’t. I can’t . . .’

‘Girl.’ Her voice floating above me. ‘You thought it was a question?’ Even with my eyes closed I could feel her staring. ‘You going have to make yourself useful or make yourself scarce.’

But she let me stay put. Through the shakes, the terrible needles pricking my flesh. Laudanum can be pure bliss going in, yet it’s nothing but pain to rid yourself of it. I vomited, I sweated, I slept. Each time I woke I barely knew my own name. You wouldn’t wish it on a dog you were trying to kill. I heard Sal come and go, felt her hands. A week of that and you could say I was weaned, in the sense that the drug made me sick even to think of it. But I couldn’t cure myself of the longing to go back. Not even Sal could help with that. Memory was a hook, twisted in my gut.

Now I was well again, and working. Sal came into my room, as was her habit every morning. She perched on the tub, and lifted one of my feet into her hands. But she took one look at my face, clucked her tongue, and dropped it. ‘You still fretting about you white woman?’

She hated when I spoke of Madame, so I didn’t answer her, but rose instead, flooding the rug, pulled on my dressing-gown. From the window, I could see Mrs Slap. Bible in hand, black-bonneted, fat. Wide everywhere except her eyes, which she narrowed at me, then at the street. ‘Whosoever shall be ashamed of me and my words in this adulterous and sinful generation,’ she called out, ‘of him also shall the Son of Man be ashamed!’

To the neighbours, Mrs Slap was Mrs Austen, a widow from Cornwall. We were her darky maids, Sally and Frances. I still thought it a miracle that she’d said I could stay, which made Sal laugh. ‘Don’t mistake that for charity. You going earn her plenty. White coves go mad for nigger gals! Two things they can’t get enough of. Flogging. Them all raised up on it. They get the taste in school and then for ever after either got to be giving a whipping or getting one. And sugar. The browner the better. And you a mulatta to boot!’