As one would expect, Bauer is punctilious with detail and willing to explain each and every choice of words he utters on complex questions. Sensitised to the paramount necessity of accuracy, he will overlook the nuance of a question to emphasise an important detail.

Holocaust denial which, Bauer observes, has been with us since the end of the war, if not in fact during it, must represent the biggest explicit and implicit challenge to a lifetime of scholarship on the subject. Bauer is unfazed. "The Holocaust deniers concentrated on certain details which were not really important, but they made us – and that may be, if you like, a kind of a positive influence – they made us check and prove what we had always said. It was not so difficult to do, by the way," says Bauer changing tone as if to reveal a confidence on a matter that flummoxes lesser intellects, "because, for instance, in the case of the gas chambers at Auschwitz, they tried to take samples from the walls of the buildings and drilled into the walls and what they drilled out they said had no contamination from Zyklon B. They of course had absolutely no knowledge of chemistry, because had they had any, they would have known that the only place where you can find such deposit is in the first one or two millimetres of a wall. Other times [samples] were sent to chemical laboratories and of course traces were found."

Be that as it may, have revisionists like David Irving successfully masked their political campaigning as a freedom of speech issue? Irving’s humiliating defeat in last year’s libel trial in London saw the presiding judge, Mr Justice Gray, dismiss him as a political propagandist and anti-Semite.

"The public I think, ideally should react with ridicule and many of them have. The majority of the British press has ridiculed Irving from the very beginning." But Bauer cautions, "The trial has not stopped Holocaust denial and will not stop Holocaust denial. It has given it a serious blow."

In line with the emergence of the Holocaust as seminal event in the history of Western civilisation, a growing discipline of comparative genocide studies has emerged to ascertain the similarities and distinctions between the Holocaust and other instances of genocide. Ever careful, Bauer repudiates the idea that this branch of inquiry is well-advanced. "Not yet burgeoning. It’s very rare actually and its just developing. The difference between the Holocaust and other genocides – of course the Holocaust was a genocide – lies not in the suffering of the victim. No victim of a murder suffered more than the victim of another murder. So it’s not the suffering that makes the difference. It was basically the concept of the Nazis to murder every single person they define as a Jew everywhere in the world for reasons that have very little to do with any pragmatic considerations. And that is unprecedented."

In recent books and articles, Bauer makes the point of avoiding the term ‘unique’ in reference to the Holocaust. But if there was nothing quite like it before or since, why does Bauer shy away from it? "Every historical event is unique," he explains carefully. "It cannot be cloned exactly. So when I say ‘unique’, it stands completely apart from any kind of similar genocide attack, which is not true. When I say ‘unprecedented’, I mean that it never happened like that before but because it happened like that during World War II, it can happen again. What has happened can be repeated. The Holocaust had no precedent, but it is a precedent."

"The Germans murdered their Jewish armament workers when they needed arms. They accused them of being the rulers of the world when in fact the world was dealing with the Jews as a very unpleasant minority who nobody cared about. So no connection to reality, you see, and there’s no precedent for genocide committed on those terms."

So what caused the unprecedented to happen? Bauer dismisses appeals to Christian anti-Semitism even as he recognises it as a necessary condition for the Holocaust. The Nazis, he explains, "had no concern about the Jewish religion. It was purely ethnic, national, racist. The origins lies in the two and a half thousand year old anti-Jewish propaganda sentiment – which we call anti-Semitism, which is the wrong term, but never mind – which precedes Christianity but then snowballs during the Christian take-over of the culture of Europe, and then Islam. But the Nazis did not use Christian anti-Semitism as such. Now racism was an idea that was developed especially in the second half of the nineteenth century and they wanted to establish a world hierarchy of nations, a new society. So, in that sense, the Nazis advocated the only real revolution of the twentieth century, because they wanted to say something absolutely new and they saw in the Jews the ultimate opponents of such a racist society. Which is a great compliment, actually, to pay to the Jewish people."

Today the Holocaust is widely memorialised as a seminal event in the history of Western civilisation. But the means are sometimes criticised. Washington DC’s Holocaust memorial has been one bone of contention.

"Well, I’m not objective," responds Bauer "because I was one of the people who advised on the content of the museum. I think it serves a very important purpose, because it presents society at large in a confronting way – obviously you can pick holes in it, here its underdone, here its overdone, or whatever – but it’s a very powerful and concise statement of what happened. The same applies to Yad Vashem. If the question is, should we have had more museums or more education, then obviously the answer is more education, but that’s not to say that the museums do not fulfil an important function. My point is that we need more investment in education."

As writer Ian Buruma noted some years ago, other groups have envied, as it were, the tag of victimisation as an identity-forming device. Jews themselves discuss the extent to which the Holocaust can or should inform contemporary Jewish identity.

"I think that’s all wrong," avers Bauer. "The Holocaust is part of Jewish identity, an inevitable part because it happened and it influences us and it’s a trauma in which we live. But Jewish identity is much wider than that. It consists of traditions, whichever way you want to interpret them, religiously or not religiously, over thousands of years. You cannot compress a civilisation into a trauma of mass-murder that happened fifty, sixty years ago."

The Holocaust casts its ghastly pall even over the Arab-Israeli conflict. Bauer agrees that Palestinians attempt to draw on the Holocaust in their own assertion as victims.

"Yes, to a certain extent. You see there is a very troublesome phenomenon in Palestinian society of denying the Holocaust, not just saying we are the victims of something that happened in Europe, but actually saying that it never happened. There are Palestinian intellectuals who work against that. But this kind of propaganda you can find in newspapers, speeches and statements and of course this echoes what happens in Egypt, Syria, Saudi Arabia and other places, where Holocaust denial is active and well."

"In actual fact," notes Bauer, developing his train of thought, "Israel is not the product of the Holocaust. The Holocaust actually prevented the establishment of a very strong Jewish community in Palestine because it murdered the people who would have gone there. The establishment of Israel hung by a thread. It was the survivors of the Holocaust who played a tremendous part in laying the ground for the possibility of the Palestinian Jews fighting for their independence. Had there been more survivors, there would have been more Israel, so to speak. The Holocaust is actually something that acted against the establishment of the state of Israel. So when the Palestinians say ‘we paid for what happened to the Jews in Europe’, it’s exactly the other way around."

"The Palestinians certainly suffered from Zionist settlement, there is no place to deny that, but the Zionist settlement is the settlement of a people who regard that area as no less theirs than the Palestinians do. The problem is to find a proper compromise between two positions. There is no question of a genocidal intent, as far as one can see, on either side. It’s a question of two nationalities fighting over a small piece of land, and both of them are right, and both of them recognise it, in a sense."

Bauer pauses, then laughs ironically before adding, "At least many Jews recognise the rights of the Arabs. I haven’t found an Arab yet who really recognises the Jewish position. The effect of the Nazi regime and the Holocaust on international politics is quite amazing. Any opponent who you will have you will call a Nazi. This is nothing unusual, however it has a deleterious effect. You become the victim of certain ideological stance. You don’t see the reality.

"The Nazi phenomenon is not something that anything in the Arab-Israeli conflict can be compared to. You wouldn’t compare the situation between India and Pakistan to genocide. It’s a national quarrel over a piece of land. These comparisons are absolutely besides the point."