He pulls a cord which unfurls a large white banner on the front wall. A poem is displayed in large black letters:

Keep your blood pure,

It is not yours alone,

It comes from far away,

It flows into the distance.

Laden with thousands of ancestors,

And it holds the entire future!

It is your eternal life.

‘Eugenics. The beautiful science of race and genes,’ Herr Metzger begins in a soft, syrupy voice. ‘Human progression is on the brink of a new era. The possibilities of a super race, free from crime, free from hereditary diseases and free from insanity, is within our grasp. This is the essence of scientific advancement.’

The floorboards creak as he walks back and forth in front of us. His fair hair is greased back and his light blue eyes twinkle.

‘The result? A population of the best: the fittest, bravest, most beautiful, cleverest, and robust. The epitome of Darwin’s theory. A people who will be superior in every way and who must spread their influence throughout the world. This is the vision behind the science. And who would not dream of such a world?’ He stops and scans our faces. I lock my knees together, sit up straight.

‘He’s rather a dish, don’t you think?’ Erna whispers in my ear.

‘Shh.’

‘All right, teacher’s pet,’ she giggles.

I dig her in the ribs.

Herr Metzger talks of population projections and the societal cost of supporting growing numbers of physically disabled people, not to mention the insane, the epileptics and the feeble-minded. He shows us the different races and their place on a Darwinian scale of advancement – Nordic at the top, Jews at the bottom. The French, thankfully, are not too far below the Germans. Lucky Mutti is from near Paris. The population in the South of France has been infected by North Africans and can no longer be considered racially pure.

The hall is hot and Herr Metzger removes his jacket. Erna is all attention now. She giggles at his informality.

‘It is vital,’ Herr Metzger goes on, ‘that Aryans breed only with other Aryans. Interbreeding with inferior races will ultimately cause the fall of Western Civilisation, just as it once did to those ancient civilisations of Greece and Rome. For those with hereditary diseases, sterilisation is essential. It is not the fault of those unfortunate individuals, but they cannot be permitted to pass their… afflictions on to future generations. For the good of all mankind, this is an inviable truth.’

I think of how Hitler sometimes speaks to me, so very clearly, inside my head. Not for the first time, I wonder with a pang if I have some kind of madness. People say, if you hear voices… I can feel my armpits are damp with sweat, my back clammy.

Is sterilisation painful? I stare at Hitler’s portrait dominating the big wall behind the teachers sitting at the front.

Am I mad?

No, Herta. I have chosen you.

But I’m a girl!