Dr Rothmann’s place was in a poorer street. He was a good doctor, Erik had heard Mother say, but he treated a lot of working-class people who could not pay high fees. The doctor’s house had a consulting room and a waiting room on the ground floor, and the family lived upstairs.

Outside was parked a green Opel 4, an ugly little two-seater unofficially called the Tree Frog.

The front door of the house was unlatched. Erik walked in, breathing hard, and entered the waiting room. There was an old man coughing in a corner and a young woman with a baby. ‘Hello!’ Erik called, ‘Dr Rothmann?’

The doctor’s wife stepped out of the consulting room. Hannelore Rothmann was a tall, fair woman with strong features, and she gave Erik a look like thunder. ‘How dare you come to this house in that uniform?’ she said.

Erik was petrified. Frau Rothmann was not Jewish, but her husband was: Erik had forgotten that in his excitement. ‘Our maid is having a baby!’ he said.

‘And so you want a Jewish doctor to help you?’

Erik was taken completely by surprise. It had never occurred to him that the Nazis’ attacks might cause the Jews to retaliate. But suddenly he saw that Frau Rothmann made total sense. The Brownshirts went around shouting: ‘Death to Jews!’ Why should a Jewish doctor help such people?

Now he did not know what to do. There were other doctors, of course, plenty of them, but he did not know where, nor whether they would come out to see a total stranger. ‘My sister sent me,’ he said feebly.

‘Carla’s got a lot more sense than you.’

‘Ada said the waters have broken.’ Erik was not sure what that meant, but it sounded significant.

With a disgusted look, Frau Rothmann went back into the consulting room.

The old man in the corner cackled. ‘We’re all dirty Jews until you need our help!’ he said. ‘Then it’s: “Please come, Dr Rothmann”, and “What’s your advice, Lawyer Koch?” and “Lend me a hundred marks, Herr Goldman”, and—’ He was overcome by a fit of coughing.

A girl of about sixteen came in from the hall. Erik thought she must be the Rothmanns’ daughter, Eva. He had not seen her for years. She had breasts, now, but she was still plain and dumpy. She said: ‘Did your father let you join the Hitler Youth?’

‘He doesn’t know,’ said Erik.

‘Oh, boy,’ said Eva. ‘You’re in trouble.’

He looked from her to the consulting-room door. ‘Do you think your father’s going to come?’ he said. ‘Your mother was awfully cross with me.’

‘Of course he’ll come,’ Eva said. ‘If people are sick, he helps them.’ Her voice became scornful. ‘He doesn’t check their race or politics first. We’re not Nazis.’ She went out again.

Erik felt bewildered. He had not expected this uniform to get him into so much trouble. At school everyone thought it was wonderful.

A moment later, Dr Rothmann appeared. Speaking to the two waiting patients, he said: ‘I’ll be back as soon as I can. I’m sorry, but a baby won’t wait to be born.’ He looked at Erik. ‘Come on, young man, you’d better ride with me, despite that uniform.’