Dovidl turned his hands outwards, signalling acquiescence to a collective fate. The big man sighed, then asked his name. ‘Perhaps I can help you,’ he said.

‘Some other time,’ said Dovidl evasively. ‘Right now, I need to find a seventy-three bus. I am expected in town.’

‘You don’t want to know if, perhaps, any of your people survived?’

The challenge was so direct, it struck him beneath the breastbone. His heart pounded in response. ‘What do you mean?’

‘We have people here who were in the Warsaw ghetto, later in the camps. They have excellent memories.’

‘You were there?’ said Dovidl.

‘I was there,’ echoed the giant, introducing himself. ‘Chaim-Yossef Spielman, once from Medzhin, then Warsaw, Treblinka, Auschwitz, displaced-persons camp, Antwerp, Stamford Hill, sholom aleikhem. Peace upon you.’

How sheltered his world had been, thought Dovidl. While this man had gone from freedom to slavery, from hell to redemption, he had gone from St John’s Wood to Trinity College, Cambridge. Spielman was his first survivor from Warsaw. He looked nothing like the cadaverous victims shown on the newsreels. Spielman was burly, self-possessed to the point of insolence. He outshone Dovidl in confidence, as Dovidl had outshone me. Against his nature, Dovidl felt himself turning from pack-leader into submissive follower.

‘I must be home by four thirty,’ he stipulated, calculating his time to the last free moment.

‘Don’t worry,’ said Spielman, in carelessly accented English, ‘we will get you home once we have helped a Jew to find his family.’

They walked together into the warren of streets that bordered the railway bank. Step by step, Spielman took his history with terse, impersonal questions. When had he got out? How many left behind? Cousins? Second cousins? All in Warsaw? Anyone in America? The questionnaire sounded practised, unnervingly routine.

They stopped at the open door of a run-down residential house and walked inside. The ground-floor room was unusually large. The partition walls, he realised, had been removed to create a low-ceilinged prayer-hall. The street windows were whitewashed to deter snoopers and the only light was artificial, two strips of neon and a pair of tinny candelabras. Two dozen men and boys sat around the perimeter of the room, swaying and chanting at single lecterns. Spielman strode to the centre, slapped his hand on the Torah stand known as the bima and announced: ‘I have a Rapoport from Warsaw.’

The chanting dimmed, there was a furrowing of brows. A smooth-cheeked boy slipped out, returning a moment later with a stooped thin man, straggle-bearded in a shining-clean silk capota. He was not more than a year or two older than Dovidl. All stood.

‘This is Dovid Eli Rapoport from Warsaw, Rebbe,’ said Spielman, inclining his head respectfully.

‘Sit,’ said the man he had addressed as ‘Rebbe’, indicating chairs. Dovidl inspected him frankly, searching for the authority to which the powerful Spielman had deferred with such humility.

‘Sholom aleikhem,’ said the Rebbe, shaking Dovidl’s hand.