We sat upstairs on the homeward-bound seventy-three bus, Dovidl admiring the view over Hyde Park, my father deep in thought. This was a critical juncture for Dovidl, and I had to lead the way.

‘May I make a suggestion?’ I ventured.

‘Is it about David?’ said Father.

‘Do you remember the old man who came to dinner at New Year,’ I began, ‘the one who was concertmaster of the Leipzig orchestra for forty years until the Nazis roughed him up and threw him out?’

‘Dr Steiner, you mean?’

‘That’s the one. Well, he has a fantastic amount of musical experience, hasn’t he, and he seemed to be extremely well read. He talked to me about Goethe, Heine, Karl Marx, Thomas Mann – and who’s the chap who wrote Bambi? Felix Salten. Might he be the sort of moral tutor you are looking for?’

‘Not a bad idea,’ said Father. ‘Dr Steiner knows orchestral and chamber music inside out – he used to have a famous string quartet – and he is a cultured man. He played Mozart with Albert Einstein, who is an enthusiastic amateur violinist, and he has a doctorate in something esoteric. Icelandic sagas, I seem to remember.

‘It would be a noble thing for us to put some work his way, and I am sure he can expand David’s mind, if he pays attention. But Dr Steiner is getting on. He can’t be expected to exert discipline. He can do the Bildung, not the hard grind of building a career.

‘Who is going to keep an eye on his technical progress? Who will make sure he practises every day and doesn’t skip the tricky bits? Who will encourage him to persist with Prokofiev, when his fingers are aching and the notes are swimming on the page? Who will inform me of any difficulties that may arise?’

‘How about me?’ I intruded.

‘You?’ said Father, politely stifling disbelief.

‘I am his friend,’ I said boldly. ‘He trusts me. I am also your son, heir to the business as you keep saying. Let me help him, supervise him and report to you, should he need anything. I don’t think he needs much encouragement.’

‘That’s a very mature undertaking, Martin.’

‘I am,’ I puffed, almost ruining the effect I had contrived, ‘very advanced for my age.’

‘Of course you are,’ laughed Father, half proud, half patronising. He patted his pockets for something to smoke, buying himself time to consider my offer. ‘This could involve you in a conflict of loyalties,’ he warned. ‘What if there is something that I need to know but which your friend does not wish me to know?’

‘I know where my loyalties lie, Father,’ I lied.