Arbuthnot Bailey, who must have been all of seventy, greeted us in puffed shirtsleeves and a velvet waistcoat, looking for all the world like a Dickensian clock-maker, by appointment to Queen Victoria. He appraised the young pretender with weary eyes that had seen them all, back to the mighty Josef Joachim, for whom Brahms had written his autumnal concerto. He took Dovidl’s right hand as if to shake it, but nursed it instead in his palm like a precious ornament, testing its weight and filigree work. He then took the left hand, holding it by the tips of its long and supple fingers. ‘A Guadagnini, I should say,’ he finally growled, ‘more receptive to your touch than a Strad. At least for the present.’

A player would no more question Baileys verdict than he would a tailor’s inside-leg measurement. ‘Come this way,’ beckoned the old man, leading us into a low-lit backroom, held at constant temperature and humidity by whirring fans and the aura of majesty. ‘This,’ he said, extracting a violin from a baize-lined case, ‘is the work of Giovanni Battista Guadagnini, 1742, the best I have seen. It used to belong to Hubay, the great Hungarian, then to an amateur collector, who let it run riot. It needs to be taken in hand by a young master, trained again and tamed. Here, try.’

Dovidl received the instrument in his right hand, turned it around to see all sides, tucked it under his chin, and picked up a bow. Before playing, he ran his fingers up and down the elongated neck, as if searching for a nodal point that he could choke or snap. Holding old Bailey’s eye, he began tuning up. The air in the room stopped circulating. Two employees in the back sat stock still. Dovidl’s eyes closed. His fingers barely touched the strings when from the belly of the instrument came a sigh of acquiescence, the sound that every lover strives for in the act of love, the prelude to preordained union. He began the Bach partita in G minor.

Arbuthnot Bailey stepped forward and took the violin from Dovidl in mid-phrase. ‘Not too much,’ he said. ‘There are cracks in the varnish, she needs reconditioning. But I think you will like each other. If you have trouble, we are here to help. I will have the instrument ready for you in a week.’

At no time was money discussed. My father left an open cheque for Bailey to fill in once the repairs were complete. The violin trade functioned on trust and intuition. A Guadagnini of this pedigree would cost, at a guess, three thousand pounds – enough to buy a house in Hampstead. But the act of sale was merely the start of a relationship between vendor and purchaser. Bailey meant what he had said. If the violin did not settle with its new owner, he would take it back, no questions asked. If the player grew tired of its tone or of himself, Bailey would take in the discarded instrument like an orphan and find another to suit the artist. More than the profit from a sale, Baileys valued their standing with violinists, offering a career-long counselling and consumer service, a discreet Soho address for all their woes and insecurities. ‘When you come back next week,’ he told Dovidl, ‘we might take a look at two or three French bows that I have been keeping for the right person.’