[2] Contentious in large part for advancing interpretations of the war considered favourable to the German side and for association with far-right groups that advanced these views, by 1988 he began advocating the view that the Holocaust did not take place as a systematic and deliberate genocide, and quickly grew to be one of the most prominent advocates of Holocaust denial, costing him what scholarly reputation he had outside those circles.
In the first edition of Kershaw's book The Nazi Dictatorship (1985), Irving was called a "maverick" historian working outside of the mainstream of the historical profession.
[3] By the time of the fourth edition of The Nazi Dictatorship in 2000, Irving was described only as a historical writer who had in the 1970s engaged in "provocations" intended to provide an "exculpation of Hitler's role in the Final Solution".
Trevor-Roper argued that: "He [Irving] seizes on a small, but dubious particle of 'evidence'; builds upon it, by private interpretation, a large general conclusion; and then overlooks or re-interprets the more substantial evidence and probability against it.
Since this defective method is invariably used to excuse Hitler or the Nazis and to damage their opponents, we may reasonably speak of a consistent bias, unconsciously distorting the evidence".
[6] Finally, Trevor-Roper commented: "When a historian relies mainly on primary sources, which we can not easily check, he challenges our confidence and forces us to ask critical questions.
The British historian Paul Addison in 1979 described Irving as a "colossus of research", but criticised him for his view of "Churchill as wicked as Hitler" and as "a schoolboy in judgment".
[5] In a book review published in the Frankfurter Allgemeine Zeitung on 18 June 1979, the German historian Andreas Hillgruber for the most part offered a highly unfavorable judgment of Irving's work.
[11] In a feuilleton published in the Frankfurter Allgemeine Zeitung on 18 October 1989 the German historian Rainer Zitelmann praised Irving for having "struck a nerve" with his provocative style and aggressive assertions.
[15] The British historian John Keegan wrote in his book The Battle for History (1996): "Some controversies are entirely bogus, like David Irving's contention that Hitler's subordinates kept from him the facts of the Final Solution, the extermination of the Jews".
[16] In an article in The Daily Telegraph of 12 April 2000, Keegan spoke of his experience of the trial, writing that Irving had an "all-consuming knowledge of a vast body of material" and exhibited "many of the qualities of the most creative historians", that his skill as an archivist could not be contested, and that he was "certainly never dull".
[18] In a six-page essay in The New York Review of Books published on 19 September 1996 the American historian Gordon A. Craig, a leading scholar of German history at Stanford University, wrote about Irving's claim that the Holocaust never took place and his description of Auschwitz as merely "a labor camp with an unfortunately high death rate".
[22] Lukacs condemned Irving as a historical writer for his "twisting" of evidence (i.e. labelling Adolf Eichmann's statement before an Israeli court in 1961 that he heard from Himmler that Hitler had given a verbal order for the Holocaust as mere "hearsay").
[25] Lukacs asserted too many of the crucial statements by Irving in Hitler's War — such as his claim that Hitler foresaw Operation Uranus, the Soviet counter-offensive at the Battle of Stalingrad, or his claim that the Hungarian leader Major Ferenc Szálasi wanted to fight to the bitter end in 1944–45 (when he wished for a German-Soviet compromise peace) — were completely dishonest and untrue statements supported by references to non-existent documents.
[27] Irving had received the alleged memoir during a visit to Argentina in December 1991, when it was presented to him after he had spoken at a neo-Nazi rally and was quite proud of his find.
[28] Irving told Rosenbaum that his philosophy of history is a strictly empirical one, and that: "I tried to apply the three criteria that Hugh Trevor-Roper thought were indispensable to reading documents.
[29] Rosenbaum sarcastically wrote in his book Explaining Hitler that if Irving wanted to be considered a historian, he was going about it in a rather strange way by denying the Holocaust at neo-Nazi rallies.
[29] Canadian academic and former diplomat Peter Dale Scott has written that "even Irving’s enemies give him grudging credit for his standard historical writings.
None of this could be found back in surviving squadron war diaries, reports of casualties and losses nor in the interviews that Middlebrook had with German pilots who participated in the battle.