Eight-years-old Edgar had been taken by his nanny for a walk when they nearly collided with Hitler.

"It so happened that just at the moment when we were in front of his door, he came out. He was in a nearly white mackintosh," Feuchtwanger said.

"We were in his way. He looked at me and there were a few casual bystanders in the street. It was about half past eight in the morning and they, of course, shouted 'Heil Hitler!'. He just lifted his hat a little bit, as any democratic politician would do. He didn't give the [straight-armed Nazi] salute … and then he got into his car."

Feuchtwanger, who said several Jewish families lived in the neighbourhood, made eye contact with Hitler, who looked at him "quite pleasantly".

"I have to emphasise that if he had known who I was, I wouldn't be here," he said. "Just my name would have been like a red rag to him."

He was referring to the fact that he was a Jew, but also to his famous uncle, Lion Feuchtwanger, one of the most popular German authors of the early 20th century.

He penned a scathing 1930 satire of the Nazi leader called , which for a time ran neck-and-neck with Hitler's in the best-seller rankings.

Feuchtwanger is about to go on a German tour for his own book, starting, of course, in Munich.

He now lives in Britain, his parents having bought visas in 1938 that would save the family's lives just as the noose was tightening around Germany's Jews.

Feuchtwanger believes that as a child he had a keener sense of what his thoroughly German Jewish parents and their friends could not believe, which was that the country they loved would turn on them.

"We were aware of the threat probably even in 1932," he said. "But of course we didn't realise how radical that threat was, how lethal it would get. My father had got that quite wrong."

That changed during the pogrom of November 9 and 10, 1938, when his father, Ludwig, who worked for a publishing house until he was stripped of his job, was swept up in the mass arrests.

He was seized at their flat, within view of Hitler's front window, and held at the Dachau concentration camp north of Munich for six weeks.

Lion Feuchtwanger had already fled for France in 1933 because his books were banned and burned by the Nazis.

He and a few other relatives pooled together to give Ludwig the large sum for those days of £1,000 upon his release that would allow the family to escape. Edgar, then 14, was sent to England first and his parents joined him two months later. His aunt Bella, however, stayed behind in Prague and would die at the Theresienstadt concentration camp.

Feuchtwanger went on to study at Cambridge, marry a British general's daughter and become a history professor at the University of Southampton.

He said leading French journalist Bertil Scali approached him with the idea of a "literary" memoir,

The book, published in French in 2012, came out in German last month and has drawn wide media coverage, with Munich-based national daily saying it read like a "spooky fairy tale, more Franz Kafka than the Brothers Grimm". Feuchtwanger is still seeking an English publisher.