‘I greeted him in English, then Polish, and got no response. I had been warned not to mention his father – or the rest of his family, who perished in Poland. The blonde from Reception stood at the door, ready to shout for help if he attacked me. I didn’t know what to do, I just wanted to register on his consciousness, or whatever was left of it after the shock treatment.

‘On his bedside table lay a cheap mouth-organ, like the one that vagrant – Kevin, was it? – used to play. I reached towards it. He snatched it away, put it to his mouth, breathing in and out – an incoherent music. I remembered his recording of a Dvořák melody and wept within for what was lost.

‘I had to get through to him, somehow. I could not leave him alone. I tried Yiddish, the Mameloshen, our mother tongue. “Yossl,” I said, “vie geyts? ” He looked up at me like a rabbit with its leg in a trap. “Aroys fin daw,” he mouthed, “sakonos nefoshos” – get out of here, your life’s in danger.

‘ “ Fan vus? ” I asked – what from? – but he said nothing more, just looked down and resumed his swaying and droning, his wailing on the harmonica. He is not much older than us, Mottl, twenty-six at most, but he was hunched up like a pensioner in a bath-chair, waiting for the end.

‘What could I do? I kissed him on the forehead, promised to come again and ran – ran like a lunatic down the stairs, through the grounds and out of the gates before I realised I had left my folder with all the experiment notes in his room. When I returned, the briefcase was waiting for me at Reception but Josef was silent – gone to therapy, the blonde said. “Is there hope of recovery?” I asked. “If you believe in miracles.” She smiled. “Schizophrenia this severe seldom responds to treatment.”

‘I was livid, could have hit her. To her, he was just another war victim, but to me he was a paragon, the best there has ever been. And I wondered if he wasn’t an oracle, sent to save me from a terrible mistake. He had told me to get out. I was in danger. Israel, gambling, Cambridge was not where I was meant to be. I had to get up on stage and play the violin. That’s the place for Josef and me. He might not make it again, so I had to do it for him, to fulfil our purpose. I stood there in the lobby almost in a trance, until the blonde asked if I wanted to see a doctor – and then, believe me, I got out bloody fast.