Kayssler finished and bowed in gratitude to the crowd’s applause. Robert Ley took his place – the head of the German Labour Front, the official state replacement for the banned trade unions, which ran the KdF. Fighting some worsening stomach cramps, Ulli let Ley’s words wash over him, straining his ears beyond the man’s slightly peculiar diction – was he drunk? – for any strand of music seeping out from backstage. But one more speech remained; this time, the figure Ulli prayed nightly that he might never need to see at close quarters again.

A blanket of silence smothered the theatre as Goebbels prepared to speak.

‘Today,’ the minister of propaganda intoned, ‘thanks to the generosity of the Führer, Schumann has entered Valhalla!’

The concerto started at last, with a pulsing on the strings and a rush of sound. Not as much of a rush as Ulli would like; Böhm was not noted for sprightly tempi. This was portentous, stately, ceremonial; it squared with the Reich aesthetic, less so with the personality of the composer. Kulenkampff, waiting for his first entry, betrayed no emotion; when his opening phrase arrived, it sounded all in a day’s work. Ulli tried to imagine how he must feel. Soloist in the first performance of a concerto on which hung so much expectation, playing to Hitler and Goebbels. Was this really the opportunity for which poor Jelly had longed?

He glanced at Hitler, in the dignitaries’ box. The Führer seemed absorbed, his head and hands moving jerkily, as if, deep down, he had discovered a would-be conductor who was longing to get out, take control and make the music move just a little faster.

Ulli was wishing to high heaven he had not eaten the smoked herring.

The slow movement began. Schumann’s violin solo seemed disconnected from the cello’s counter-melody: drifting over the top, lost in his own world, or perhaps trapped there. Heads turned; people glanced at their companions to see if they, too, were puzzled. Was it meant to sound like this? Was Kulenkampff’s timing wrong? Ulli, who had worked on every note of the piece, knew it was right. If Kulenkampff and Böhm, those most rational musicians, could not make sense of the concerto, how could anybody?

And yet… within this musical jungle lay a naked beauty so exposed that it seemed almost indecent. Schumann’s soul might be damaged and suffering, but he still gave its entirety. Could it ever have been right to leave this music unheard?

And yet, and yet… there was madness here, a precipice lying ahead in the fog and snow; a spirit filled with love, but lost, unable to master itself. For the first time, Ulli began to wonder what happens when insanity is unleashed through art into the souls of others. What exactly did Joachim and Clara know about this piece that made them put it to sleep?