Hitler and Eva Braun ‘had sex without touching each other or taking their clothes off’ because he was so fanatical about hygiene, says author Martin Amis.

Speaking at the Cheltenham Festival of Literature, the novelist claimed he believes the German dictator kept Eva at arm’s length and would achieve orgasm just by watching her lift her skirt.

He also claimed that Hitler was an asexual and may have had a similar kind of sexual relationship with his half niece, Angela ‘Geli’ Raubal.

Scroll down for video

Adolf Hitler pictured with long-term lover and wife Eva Braun who 'had sex without taking their clothes off'

Amis told visitors he imagined the leader of the Nazi Party ‘would fortify his underpants with clean serviettes and then would go into some form of excitation with Eva Braun at a safe distance’.

He said: ‘I imagine Eva would stand a good distance away and lift her skirt and then there would be some sort of soggy climax on Hitler’s part and that would be that.’

The award-winning writer was speaking about his second Nazi-era novel, ‘Zone of Interest’ which is being released 23 years after his first, ‘Time’s Arrow’, was published.

And although he feels he has come to know Hitler well, he maintains the truth about his sexuality remains a ‘black hole’.

Author Martin Amis made the claims while speaking at the Cheltenham Festival of Literature yesterday

‘Sexuality is one of the ways we recognise each other,’ he said

‘Knowing whether someone is married or gay or whatever it might be, you recognise that.

‘I don’t want to be reductive, simplistic or frivolous but I am convinced one of the reasons why Hitler is an unrecognisable figure is that sexually he is a void.

‘With Stalin or Mao there is clear pattern seigniorial behaviour - of having a big appetite – but with Hitler there is absolutely nothing.’

His explanation is that Hitler was ‘not quite the full quid’ and may simply have been insane.

‘In Hitler studies there are three schools of thought about Hitler’s sexuality.

‘One is normality but I think you can boot out that consideration immediately. Can you see Eva Braun relishing a post coital cigarette? Can you consider Hitler’s tender foreplay, a considerate and energetic lover? No you can’t begin to imagine that.

‘So I’d say normality is out. Asexuality is the other one - and the third one is perversion.

‘Historians and psycho-historians who adduce perversion all come up with the filthiest stuff you could possible imagine - coprophilia, coprophagia, all things to do with excretion.”

‘But there are no real clues about his sexuality - except that he wouldn’t take his clothes off, even for his physician and he was almost fanatical about cleanliness, which suggests to me asexuality plus.’

In his latest book he explores the horrors faced by thousands of Jews when they were sent to concentration camp Auschwitz.

The author said one thing which had shocked him during research for the book is that the Nazis had their wives and children living with them in the death camps.

Amis claims that Hitler kept Eva at arm’s length and would achieve orgasm just by watching her lift her skirt

Hitler asleep in an armchair next to Eva Braun in the teahouse on the Eagle's Nest in Berchtesgaden

Hitler kisses the hand of Eva Braun, in 1941. Author Martin Amis claims Hitler was an 'asexual' and insane

He also discovered how Jews had to pay for their own train fares to the camps - one-way tickets and with children under-12 going free.

Martin Amis was speaking about his second Nazi-era book 'The Zone of Interest' at festival yesterday

But even though he was gaining in knowledge, Amis said he had still not discovered the reason for Hitler’s policies, particularly the hatred of the Jews.

‘One can’t understand the Nazi hatred because it’s anti-human, it’s counter-human.

‘It is a hatred that is not in us, it is outside man.’

Amis dubbed Hitler ‘a bourgeois anti-Christ’ and also spoke of his concern for the high percentages of people in many countries who remain anti-Semitic to this day.

A survey of Greeks showed 69 per cent were anti-Jew, possibly proving that a country in economic crisis was more likely to feel hostility towards Jews, who are seen to be clever, successful and better off.

He also said 93 per cent of Iraqi and Saudi Arabian people are anti-Semitic while Iran is the most benevolent country in the Middle East with ‘only’ 56 percent disliking Jews.

In England the figure is eight percent and in Sweden just four percent, he added.

Amis believes that for some reason Jews inspire either love or hatred in people - his own first love was a Jewish girl - and that few remain neutral on the issue.

He is planning on writing a third novel set against the same grim backdrop.