Dovidl’s determination was fierce and his self-tuition was assisted by my readiness to plink out rough accompaniments on the piano any time he asked. Before my amazed ears, he invented and perfected his time-stopping rubato – which, if memory does not mislead, he adapted from a practical tip by Auer, Heifetz’s teacher. With me as personal listener, he picked up speed and mastery without shedding grace and wit. There was no doubt in my mind that he was destined for greatness.

By the end of that first severe winter, Dr Steiner declared him ready for a public début. ‘I have such joy from the Kinder,’ he told my father, who confided afterwards that Steiner’s daughter and grandchildren had been unable to leave Germany in time. ‘Not only from the artist Kind , but from der andere as well.’ He beamed, indicating me. Dr Steiner had been refusing to accept the envelopes that I thrust on him with payment, which is why I had called Father in.

‘Dr Steiner, I cannot let you teach them for nothing,’ he objected.

‘Is nichts for nothing,’ said Steiner. ‘They are my future.’

A solution had to be improvised. Mrs Steiner was deteriorating fast and Mother arranged for the couple to be housed, at our expense, in a refugees’ nursing home in Belsize Park, a Spartan, bare-floorboarded establishment, but one that offered more care, comfort and human company than the leaky Carlton Hill garret. Each Wednesday, after our session with Dr Steiner, Dovidl gave an impromptu ten-minute recital in the residents’ lounge to cries of ‘Herrlich! ’ and ‘Wunderschön! ’

A return visit to Albert Sammons reinforced Steiner’s endorsement.

‘He’s ready, y’know,’ said Sammons. ‘I’d give him the Elgar, Simmonds, and put him in front of an orchestra tomorrow.’

But Mortimer Simmonds performed at his own tempo. ‘Not yet,’ he told the mentors, ‘there’s plenty of time. He must grow some more, physically and emotionally. In his father’s absence, I have a paternal responsibility towards him.’

The most my father would permit was a private recital with a professional accompanist (At the Piano: Ivor Newton) in our Blenheim Terrace piano room. Father invited Sammons with his star pupil Thomas Matthews, recently appointed leader of the London Philharmonic Orchestra; the famed viola player William Primrose; the Steiners, together with several émigré composers; a music-loving Harley Street physician, Dr Edward May; and the conductor Sir Henry Wood.

Mother worked on her invitation list for a month. Her prize catches were two Rothschilds and the Chief Rabbi’s wife; the rest of her allocation consisted of Sephardic relatives and wealthy ladies of the Wood. She had an outfit made for the occasion. Caterers were called in. A spare piano was hired, in case our Steinway developed last-minute woodworm. Nothing was left to chance.