An unrepentant David Irving today maintained his denial that Adolf Hitler oversaw an organised attempt to exterminate Europe's Jews.

Speaking from jail in Austria, where he was sentenced to three years imprisonment last week for denying the Holocaust, the disgraced right-wing historian questioned whether the Nazis could have really intended to wipe out all the Jews held in concentration camps if, as he claimed, so many had survived the experience.

"Given the ruthless efficiency of the Germans, if there was an extermination programme to kill all the Jews, how come so many survived?" he said, in an interview on BBC Radio 4’s Today programme.

During his one-day trial in Vienna last week, when he pleaded guilty to denying the Holocaust in two speeches made to Austrian neo-Nazis in 1989, Irving acknowledged that he had made a mistake in denying the existence of gas chambers at Auschwitz, the most infamous Nazi camp.

He claimed that he personally had identified two small buildings where gassings occurred - but he pointedly ignored the weight of historical evidence that points to mass executions in an enormous purpose-built crematorium where victims were first gassed then their bodies burned.

Today, the British academic repeated his assertion that the number of Jews killed at the camp was relatively small, and certainly much smaller than the figure of 1.1 million that is generally accepted by Holocaust historians.

"There were these two small buildings where gassings were done, but I think we can be very argumentative about the scale of it," he said. "Certainly, anybody who suggests that this was the heart of the Nazi programme is way off track."

Irving said he accepted that 1.4 million Jews were killed at the so-called Reinhard extermination camps of Sobibor, Belzec and Treblinka, but he insisted Auschwitz was different: "You can say millions died, but not at Auschwitz."

The story of Anne Frank, according to Irving, backs up his argument: "The Anne Frank family wasn’t gassed, although they were in Auschwitz," he said. "When they fell ill, they were looked after by SS doctors, and two of them survived. The whole Anne Frank story is proof that I am right."

He also questioned the responsibility of Hitler for the 20th century's greatest crime. Asked whether he believed that Hitler had overseen the Holocaust, Irving replied: "No. That is absolutely wrong and nobody can justify that.

"Adolf Hitler’s own involvement in it has a big question mark behind it."

Irving, 68, was shocked to receive a three-year sentence at his trial under Austria's stringent Holocaust denial laws last week.

He is spending 23 hours a day in solitary confinement at the start of his punishment, which Austrian prosecutors are seeking to extend to 10 years because of Irving's "special importance to rightwing radicals". Irving is also planning to appeal. But today's outburst is unlikely to help his claim to have recanted some of his most extreme beliefs about the Holocaust.

He said this morning that his conviction was the result of a "show trial" and he promised to continue writing history.

Irving is the author of more than 30 books, but his reputation as a trustworthy historian was destroyed by a High Court libel trial in 2000 that showed that he had distorted and wilfully misunderstood sources relating to the Holocaust.

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