This was, Dovidl knew, no time to quote Scripture or Lieder. He should have felt a wave of relief at the post-mortem verdict. His parents and sisters were dead, as he had feared; but a cousin, a scrap of flesh and blood, lived on as a pioneer in Galilee. He was not alone, not without kin. In the song of death, there was life. He could seek consolation and, freed of uncertainty, start anew. But relief was refractory, denying him ease. He felt no lifting of burden, rather a great weight settling on his shoulders, rendering his arms leaden and useless. How will I play if I can’t lift a bow? he wondered briefly.

A razor blade flashed expressionlessly in the Young Rebbe’s right hand. ‘What’s that?’ said Dovidl impassively.

‘I am going to make a cut in the jacket, and another in the shirt,’ said the Rebbe. ‘The mark of bereavement.’

Spielman’s arm extended protectively, possessively, around his shoulders as the cloth was cut, then ripped, and a verse uttered: ‘ “May His presence comfort you among the mourners of Zion and Jerusalem.” ’ The men and boys echoed the benediction, lining up to shake his hand, and look away.

‘Where will he sit shiva?’ said the Rebbe, in Yiddish.

‘Bei mir,’ volunteered Spielman.

‘But I must leave,’ protested Dovidl.

‘First one must mourn,’ said the Rebbe, incontrovertibly. It was upon those words that Dovidl’s life turned.

The gale that rocked the camper van has given way to spattering hail, blown in gusts against the tin walls. Katzenberg rises, flexes his legs, pours another mug of tea and offers me a polite biscuit, mutely declined. ‘I make no excuses,’ he insists. ‘I do not want you to feel that I was acting under duress of any kind, physical or moral. I was alert to what was going on and could, at any moment, have asserted my will, got up and left. I was not their prisoner. But I was in awe of the Young Rebbe and his terrible song, and I felt sheltered by Chaim-Yossef Spielman, by his great size, his gentleness and self-assurance.

‘When I saw this giant of a man doing unquestioningly as the Young Rebbe told him, and the Rebbe himself acceding to the wishes of his dead father, whose authority stemmed from a hundred generations of rabbis and scholars stretching back to the editors of the Talmud, I felt like a foot-soldier on the field of battle, a cog in a towering machine, driven by vastly superior forces.