‘I was able to ascertain that,’ coughed Father. ‘The date of deportation was 18 August 1942, and the destination, Treblinka. That is not promising. Treblinka was an annihilation centre, not a labour camp. More than a million people were killed there, directly upon arrival. I was not allowed to visit the site – for security reasons, they said. However, I made the acquaintance of a senior official at the Ministry of Culture, Mr Kaczynski, and he has offered to make continuing enquiries at the highest level. He, too, lost relatives at Treblinka.

‘I am sorry this does not give us much to go on with, my dear David, but rest assured that I shall not give up the search. And you, David, must promise me that you will not give up hope.’

Dovidl, in a high-backed dining-room chair, waited for my father to expel another souvenir gob of Varsovian phlegm. When he finally spoke, his knuckles were white as quicklime. ‘I have no hope, Mr Simmonds,’ he said, with mathematical precision. ‘Hope is self-deception. One can have faith – in God, in art and in the evidence of eyes and ears. Faith can be validated, or refuted. But hope is futile – an illusion for the hopeless.’

He paused as Father heaved and coughed again. I stared at the tablecloth, feeling useless. ‘I had better accept the reality,’ Dovidl continued. ‘I shall never see the drawing my sister Pessia made of the baby I never saw. My parents are dead’ – he rose in a hurry – ‘my sisters . . . are no longer alive.’

I knocked at his door late that night. He was lying fully clothed on his bed, staring upwards. I told him that all was not lost, that missing children were still turning up and that any number remained hidden in haystacks and convents. Dr Schonfeld was going back time after time. It was not beyond reason to hope, I argued. The great philosophers did not discount hope: Voltaire, Descartes, even Schopenhauer. Dr Steiner had mentioned a school of thought led by one of his friends, Ernst Bloch. He called it Das Prinzip Hoffnung, the hope principle. Hope was part of our human constitution, I protested. It could not be eliminated as irrational.

‘Drop it, Martin,’ said Dovidl, freezing me with the unfamiliar formality of my name. ‘I’m trying to face objective facts. I’m not in the mood for philosophy.’

Wrenched by his misery and terrified that grief would tear him away from me, I gripped his shoulder by way of solidarity and left the room. In the corridor I bumped into Florrie, whose bedroom was opposite mine. She raised her eyebrows in sympathy and shook her irrepressibly curly head. There was nothing to be said.

Assistant Minister Goldfarb of the Abbey Road synagogue came round in black canonicals and dog-collar on a pastoral visit. He urged Dovidl to observe the shiva rite of mourning, followed by eleven months of attendance at twice-daily prayers. ‘You will find comfort each day in the heart of the community,’ he advised.