Father said: ‘God knows I’m doing everything I can to hold back Hitler and his mob.’

‘And so am I. But when you do it, you believe you’re following a sensible course.’ Mother’s face hardened in resentment. ‘And when I do it, I’m accused of putting the family at risk.’

‘And with good reason,’ said Father. The row was only just getting started, but at that moment Erik came down, clattering like a horse on the stairs, and lurched into the kitchen with his school satchel swinging from his shoulder. He was thirteen, two years older than Carla, and there were unsightly black hairs sprouting from his upper lip. When they were small, Carla and Erik had played together all the time; but those days were over, and since he had grown so tall he had pretended to think that she was stupid and childish. In fact, she was smarter than he, and knew about a lot of things he did not understand, such as women’s monthly cycles.

‘What was that last tune you were playing?’ he said to Mother.

The piano often woke them in the morning. It was a Steinway grand – inherited, like the house itself, from Father’s parents. Mother played in the morning because, she said, she was too busy during the rest of the day and too tired in the evening. This morning, she had performed a Mozart sonata then a jazz tune. ‘It’s called “Tiger Rag”,’ she told Erik. ‘Do you want some cheese?’

‘Jazz is decadent,’ Erik said.

‘Don’t be silly.’

Ada handed Erik a plate of cheese and sliced sausage, and he began to shovel it into his mouth. Carla thought his manners were dreadful.

Father looked severe. ‘Who’s been teaching you this nonsense, Erik?’

‘Hermann Braun says that jazz isn’t music, just Negroes making a noise.’ Hermann was Erik’s best friend; his father was a member of the Nazi Party.

‘Hermann should try to play it.’ Father looked at Mother, and his face softened. She smiled at him. He went on: ‘Your mother tried to teach me ragtime, many years ago, but I couldn’t master the rhythm.’

Mother laughed. ‘It was like trying to get a giraffe to roller-skate.’

The fight was over, Carla saw with relief. She began to feel better. She took some black bread and dipped it in milk.

But now Erik wanted an argument. ‘Negroes are an inferior race,’ he said defiantly.

‘I doubt that,’ Father said patiently. ‘If a Negro boy were brought up in a nice house full of books and paintings, and sent to an expensive school with good teachers, he might turn out to be smarter than you.’

‘That’s ridiculous!’ Erik protested.

Mother put in: ‘Don’t call your father ridiculous, you foolish boy.’ Her tone was mild: she had used up her anger on Father. Now she just sounded wearily disappointed. ‘You don’t know what you’re talking about, and neither does Hermann Braun.’

Erik said: ‘But the Aryan race must be superior – we rule the world!’