And then he was there. He was to awaken the Schumann Violin Concerto with a personal kiss of approval. The audience – the congregation, perhaps, of this church of political art – stood at once. Feet struck the floor. Arms swept upwards. Gathered voices rose like an aeroplane engine, and there in the box was a dark, flop-haired, moustachioed figure, arm outstretched in salute, gaze scouring the crowded theatre beneath. The cheering assaulted Ulli’s eardrums. Having no choice, he stood too, and saw his own arm rise to match the angle of everyone else’s, because it would look very obvious if it did not, and it occurred to him that he had never in his life seen or heard anything like this roar of heightened energy in one mass of people.

He noticed a woman in early middle age occupying the seat beside his. She had not risen to greet the Führer, but sat in her chair, immobile.

‘Why aren’t you standing?’ someone behind her challenged.

‘I have a bad knee,’ said the woman over her shoulder. Then she stared straight ahead. Ulli noticed the man take a breath to fortify the accusation, but fortunately for his neighbour the proceedings now demanded silence.

The Führer sat, and the people followed suit. The conductor, Karl Böhm, strode to the podium. A crash of cymbals: Wagner, the grandest of the Führer’s favourites, the strings galloping through shimmering triplets, the horns bouncing along in their pomp and grandeur. The Prelude to Act III of Lohengrin. In the opera, it would introduce a wedding scene after which everything goes horribly wrong, but so stirring was its mood that now the context was ignored.

Here it was an introduction, as it turned out, to Goethe’s Prometheus; Friedrich Kayssler took the stage alone to recite. Ulli had not seen the actor, an imposing 60-something with an aquiline profile, since the days when the great man had been based at the Berlin Volksbühne – the ‘people’s theatre’ – where he had taken over from Max Reinhardt as director back in 1918. Goethe’s poem addressed Zeus as a self-appointed human deity, deriding the old gods. There was no mistaking the intent of these words in Hitler’s presence.

And the Führer? How insignificant he would look if you passed him in the street without his uniform and moustache. It was all one big show, a manufactured identity complete with music, pictures, camera angles and stage management – yet people swallowed it whole, inexplicable and irrational as that might be. Ulli’s head felt hot, yet he shivered; perhaps anxiety, perhaps the smoked fish at breakfast. There seemed to be no air in the theatre. He closed his eyes and tried to breathe deeply.