[Sereny is an Austrian-born journalist and fiction writer whose works include Into That Darkness: From Mercy Killing to Mass Murder (1974) and The True Story of the Hitler Diaries. In the following essay, she attacks the logic and scholarship of neo-Nazi apologists.]

There is a degree of indecency in entertaining a dialogue with individuals such as Richard Verrall and those of his persuasion. Nonetheless, it is necessary. We may despise them, but only at our peril do we mock or under-rate them, for the best—or worst—of them lack neither intelligence nor resources. According to the farmer and part-time publisher Robin Beauclerc (one of the original backers of the National Front), whose busy printing press produced not only Verrall's obnoxious pamphlet Did Six Million Really Die?, but also A. R. Butz's book The Hoax of the Twentieth Century, almost a million copies of the pamphlet have been distributed in 40 countries. I have seen them myself, as well as the Butz book, in schools, universities and libraries in Western Europe as well as the United States. Notoriously, both have arrived in Australia.

People who consider themselves generally well-informed say: 'But why go on with this ridiculous argument? If there is anything we know, surely, good God, we know about the horrible camps and the six million?' It is not only the World War II generation: an intelligent young person, glancing at the material on my desk, also said: 'But WHY does the New Statesman give him space? WHY take him seriously? Why spend precious time and space on refuting obvious lies?'

Time and space are indeed precious, and neither writers nor editors should squander them. There are two weighty reasons why one must pursue these debates with the Verralls, the Irvings, the Butzes and their like.

The first is that they are by no means motivated by an ethical or intellectual preoccupation with the historical truth, but rather by precise political aims for the future. As all political philosophies have needed their precursors, and parties their prophets, so they require a model, a hero, and it is of course Hitler whom they need to serve in that role. But, because people in general are good rather than evil, it must be a Hitler shown to have been not only powerful, but moral.

It does not matter that he created a police state—justification can be cobbled up for something which others have also done. It does not matter that he appropriated neighbouring lands and peoples. Ideological and demographic justifications can be devised. And it does not matter that he provoked and fought a bitter war, which cost the lives of millions. Wars have always been fought, they have always cost too many lives, and have always been 'justified'. None of these things, not even the ruthlessness with which he first pursued these aims, detract from Hitler's fitness to be the hero they seek and need.

There is one thing only for which there was no reason of war; no precedent; no justification. One thing of pure evil, and this they cannot afford to accept: the murderous gaschambers in occupied Poland, the attempt to exterminate the Jews.

Time and again in their diatribes—here again in Verrall's letters [to the New Statesman]—regardless of the mountains of evidence, regardless of the living witness, they harp on their obsessional claim: there was no holocaust; there were no gas-chambers, not to speak of. And of course they return to their polemic about the six million figure, with which they perform degrading mental acrobatics.

The second reason why we must come to grips with both the substance and detail of the neo-Nazi claims is that sometimes mistakes have been made, have been given immense publicity, and become part of holocaust lore. At the risk of offence, we must correct and explain these mistakes, in order that they cannot be exploited again.

The likes of Verrall and Butz have shown a considerable talent for mixing truth with lies, by repetitive injecting of some truth into all lies, and lies into the truth. They make astute use of human errors (and of latent prejudice). So, they have succeeded to some extent in exploiting a terrible and astonishing fact, which is that after 35 years and billions of words, confusion still abounds on the subject of Hitler's genocide.

This has never shown up more plainly than in the case of the American television film Holocaust. As a member of a BBC panel of the night of its showing, I voiced misgivings about its factual errors, and tried to explain why these would be particularly difficult for the Germans to accept. Via satellite, the producer was more than impatient with my remarks. The film was highly successful, and useful in that it provided an emotional link, for millions of people, with events which many of them had rejected because they were impossible to visualise. But, after much expenditure on research, Holocaust could not lay the misunderstandings to rest.

The current argument with Mr Verrall, for example, deals with one main element in this confusion. He makes much of what he calls the 'admission' by the Institute for Contemporary History in Munich that '… no such things (as gas chambers) existed in … Belsen, Buchenwald and Dachau … etc etc'.

This so-called 'admission' stems from a letter which the historian Martin Broszat, now Director of the Institute, addressed in 1962 to the weekly Die Zeit. Professor Broszat remembers the letter well—'How could I forget it? Neo-Nazi and far-right publications have used it out of context ever since … '

The letter was written in yet another attempt—many have been made, by many people—to set the record straight. What Broszat was trying to do, he explains

was to hammer home, once more, the persistently ignored or denied difference between concentration and extermination camps; the fundamental distinction between the methodical mass murder of millions of Jews in the extermination camps in occupied Poland on the one hand, and on the other the individual disposals of concentration camp inmates in Germany—not necessarily, or even primarily Jews—who were no longer useful as workers.

Most of the concentration camps in Germany proper had no gas chambers. Dachau had one which was never used. 'Mathausen, Natzweiler, had one. Sachsenhausen, too, I think', says Broszat. 'They used them towards the end, to replace the shootings and injections of small groups of prisoners, which had become so demoralizing for the staff.'

How is it then that the myth of gassing in the camps in Germany has been so universally accepted, thereby providing the neo-Nazis with their most treasured ammunition (the opportunity to refute what was never the case)? The explanation is both simple and infinitely complex.

German concentration camps, set up at first as SS-controlled detention centres for political, criminal and religious dissidents, and for sexual deviants and Jews, were neither then nor later primarily used for the imprisonment of Jews.

After 1940, as the need arose for an immense work-force for the war industries, the small penal camps, until then used only for Germans, Austrians and Czechs (including Jews from those countries) grew into huge installations with many hundreds of thousands of Russians, Poles and 'undesirables' from occupied Western Europe making up a vast slave-labour population.

Harshness of treatment varied between categories of prisoners. The German criminals were usually at the top of the camp hierarchy. 'Politicals' were in the middle, followed by religious and sexual deviants; with the Poles, the Russians and the Jews—in that order—at the bottom.

Millions of people died in these concentration-plus-labour camps: some—the most publicised—by torture, brutality or hideous medical experiments. But far more of them died from sickness and disease.

These were the camps that all Germans knew about and dreaded. These were the corpses found by the horrified Allied armies as they entered Germany. These made the photos and films we have principally seen. These emaciated skeletons, some still somehow upright, some lying on bunks in stupor, still others piled in naked, tumbled heaps ready for burning—these are the images that haunt us.

These people died by the million, but they were not 'exterminated' in the sense that the Nazis made uniquely their own. These camps had gas-oven crematoria, to dispose of the bodies. The chimneys belched out the smell of burning flesh, and the guards, in threat or mockery, told the prisoners: The only way you'll get out of here is through the chimneys'.

'Gassing' had been a part of the vocabulary in central Europe, and particularly in Germany proper, since the Nazis' destruction by gas of 80,000 physically and mentally handicapped people (children and adults) between 1939 and 1941. Thus, when sick or disabled prisoners in the German camps disappeared, when the chimneys smoked, and prisoner-workers reported that those missing had 'gone into the gas'—this was among men and women living in constant, deadly fear—it was not hard for 'gassing' to become a general term, used without much distinction.

The Allied troops who entered the camps had no idea what 'gassing' really was. All they knew was what they saw or heard about: the skeletons, some gaschambers, and hundreds of thousands of agonised tales and memories. As a welfare officer with UNRRA in 1945-6, I saw many of those sights, heard many of those tales, and tried to visualise those fearsome memories.

And then there was Auschwitz, and later Majdanek: the two, the only two, where the Nazis combined enormous labour installations and nearby facilities for extermination. Auschwitz, because so many people survived it, has added most to our knowledge, but also most to our confusion as between the two types of camps. What exactly was Auschwitz, which has become for many people the symbol-word for the whole Nazi horror?

It was, above all, by 1943 the largest slave-labour camp the Nazis had, with a population of 100,000 workers who were treated worse than animals, and whose expectation of life varied between ten days—if they were Jews or Russians—and a few weeks or months. Until spring 1942 it was just a small workcamp, with only the most rudimentary gassing installation. Then, I. G. Farben began to build a synthetic fuel and rubber factory—the 'Bunawerke'—on the adjacent marches, and ever-larger numbers of slave-labourers were dragged in, to build and then to operate it.

It was under the cover of constructing the Bunawerke that the Nazis made the slaves build the gaschambers at Birkenau, in a wooded area three miles from the main camp, called Camp II. It was here that, mainly in 1943, the 'selected'—mostly Jews, and some Russians—were brought from the railway sidings several miles away, and from the main camp. Also from Camp I, uniquely, came thousands of sick and feeble: not, for some mysterious reason, to die at once, but to be kept in utter squalor, virtually without rations, until they finally slipped away.

By the autumn of 1944, just over 700,000 Jews had died in the gaschambers at Birkenau (Camp II), and 20,000 Russians had been killed, but not gassed (that method was reserved for Jews). And by the time of liberation, 146,200 more Jews and several hundred thousand others had died of overwork and disease in Camp I.

Richard Verrall, busy with his vile numbers game, asserts that the confessions of Rudolf Hoss, commandant of Auschwitz, were obtained 'under torture' in Poland, were 'nonsense' and are thus 'proof positive' of a hoax.

Whatever may be said about Hoss, his role and his later manic pretensions, what really counts is that his statements to the American psychiatrist Dr G. M. Gilbert at Nuremberg were made before he was handed over to Poland, and that he said at Nuremberg almost exactly what he said in Poland—including two sets of estimates for the dead at Auschwitz. The second figure he cited each time, a total of about 1.3 million dead, comes very close to Gerald Reitlinger's most careful estimate: 700,000 Jews gassed in Camp II, and 500,000 prisoners (including 146,000 Jews) dead from exhaustion and disease in Camp I.

But this is in a sense beside the point, because Verrall and Butz, while trying to discredit Hoss, cite him whenever they hope to make a point. As they totally deny the existence of the other extermination camps in occupied Poland, Auschwitz is something of a beam in their eye. But it is important for those of us interested in the truth to recall that Auschwitz, despite its emblematic name, was not primarily an extermination camp for Jews, and is not the central case through which to study extermination policy.

The first mass murders occurred while Auschwitz was still a penal labour-camp: they followed the 'Commissar Order' of March and July 1941, which commanded the liquidation of Soviet political commissars, gypsies, racial inferiors, 'asocials' and Jews. These killings—and none of the neo-Nazis have much to say about them—were presented as para-military operations. The hundreds of thousands of naked men, women and children who were shot on the edge of mass graves were described, even to their murderers the Einsatzgruppen, as 'partisans' and 'bandits'.

But the Einsatzgruppen actions showed the Nazis that this pseudo-military method could not work for the great masses of Jews yet to be dealt with. As we know from hundreds of statements by German witnesses in the Einsatzgruppen trials in West Germany, the killings put an intolerable strain on personnel—despite liberal supplies of alcohol and sex—and provoked protests from the Wehrmacht.

However, the Nazis had a tested solution at hand. Of the 80,000 unwanted people killed in the 'Euthanasia Programme' some (but only small children) had been killed by injections in special hospital wards. Most had died in gas chambers in the Euthanasia Institutes. Over 400 men and women—police, medical and administrative staff, under the direct authority of the Fiihrer-Chancellery, in Department T-4—had done these murders.

Here was a technique, and a staff to operate it. The 'specialists' who had been prepared to kill helpless Germans and Austrians could safely be entrusted with the slaughter of millions of Jews and thousands of gypsies: eradicating, as Hitler put it, 'the bacilli on the body politic of the German race'.

Mr Verrall complains that among the vast documentation surviving 'there is not a single order … etc for a "gas chamber" '. Typically, neo-Nazi diatribes claim that there is no record of the vast transportation arrangements which would have been required to carry out an extermination programme.

Few of those who read this rubbish have an opportunity to examine the record themselves. But anyone who has actually worked in the archives is familiar with the hundreds of railway signals which survive, describing with horrible monotony the destination and contents of the trains to Sobibor and Treblinka.

And all researchers are only too familiar with the countless documents, 'orders, invoices, plans', and indeed 'blue-prints' concerning precisely the construction of gaschambers.

One of the documents (N. 0. 365), the earliest I know of concerning gassing camps (and significantly linking them to T-4) is dated 25 October 1941, and states that 'Victor Brack (Chief of Section II of T-4) is ready to collaborate in the installation of the necessary buildings and gassing machinery …' The longish letter, which concerns camps to be erected in Riga and Minsk, is quite explicit in the use the equipment is to be put to.

Thus between December 1941 and April 1942 ninety-six of Brack's T-4 men were posted to Occupied Poland and the 'Aktion Reinhard' (named after Reinhard Heydrich, killed in Czechoslovakia). They were assigned to the four specialised extermination camps, which were Chelmno, Belzec, Sobibor and Treblinka. These had been built under the command of the SS chief in Lublin, Odilo Globocnik.

These were not concentration or labour camps. The facilities provided housing for just a few German Waffen-SS, less than 100 Baltic or Ukrainian SS overseers, and a constantly-changing group of a few 'work-Jews'. Although millions arrived, no-one else lived long enough to eat, wash or sleep. These were meticulously-planned killing-plants. The official Polish estimates (which probably err on the conservative side) are that 2,000,000 Jews and 52,000 gypsies, at least one-third of them children, were killed in these four installations between December 1941 and October 1943. Of all those who reached them, 82 survived.

I am able to bear some witness to these events. My knowledge comes from research I did for my book Into That Darkness, the story of Franz Stangl, commandant of Treblinka. I talked with Stangl for weeks in prison; I talked to others who worked under him, and to their families. I talked to people who, otherwise uninvolved, witnessed these events in Poland. And I talked to a few of those very few who survived.

Butz claims in his Hoax that those (hundreds) who admitted taking part in extermination were doing so as plea-bargaining, in order to get lighter sentences. But those I talked to had been tried. Many had served their sentences, and none of them had anything to gain—except shame—by what they told me. Stangl himself wanted only to talk, and then to die. And Stangl is dead. But if Verrall, Butz & Co were really interested in the truth, Stangl's wife, and many other witnesses are still able to testify.

The 'Aktion Reinhard' camps existed for one purpose only, totally unconnected with any requirement of war, and they were totally eradicated when their purpose was served. The buildings were pulled down, and trees were planted in the earth which had become so rich. Thirty-five years later they have grown tall. A letter from Globocnik to Himmler survives, dated Trieste 5 January 1944, and carefully phrased:

For reasons of surveillance a small farm has been built on the site of each of the (former) camps, to be occupied by a farmer to whom an annuity must be assured in order to encourage him to maintain the farm …

In his own letter of commendation to Globocnik, dated 30 November 1943 Himler used his pet name for Globocnik:

Dear Globus, I confirm your letter of 4.11.43 and your report on the completion of the Aktion Reinhardt (sic)… I want to express to you my gratitude and appreciation for the great and unique services you have rendered the whole of the German people by carrying through the Aktion Reinhardt. Heil Hitler! Cordially yours, H.H.

Here, then, is the truth for those who desire knowledge. Within one terrible universe of oppression and death—known to us through words like Belsen, Natthausen, Dachau—there was another universe, of methodically crazy slaughter of an unprecedented kind—the place-names being Chelmno, Belzec, Sobibor and Treblinka. Auschwitz, the most-cited, was a complex, transitional example. There are reasons why the worst names are least cited: one, complex in its roots, is that the Third Reich tried to present its (marginally) less hideous face towards the West, and the western armies never reached the territory of the death-camps. And well-run extermination camps leave few survivors to tell their stories.

The situation therefore presents some possibilities for confusion to pseudo-historians and neo-Nazi apologists. And they are assisted further by the fact that events of such magnitude lend themselves to dramatic 'use', are therefore used, and not-infrequently misused. In turn the Verralls and Butzes can allege that all such misuses are part of a 'Zionist' conspiracy.

It is vital for them to believe that anyone who is involved with this question must be Jewish, and thus unreliable. This to begin with, is nonsense: (a) many of the leading authorities on the Third Reich are not Jewish, and (b) many of those who are, are as objective as anyone can be. (In their anti-semitic outpourings, these individuals never refer to 'Jews', but almost invariably to 'Zionists'. They know that 35 years after Hitler many people will not accept the attack on 'Jews', but many be persuaded by the more 'political' label 'Zionist'. Of course, many Jews are not Zionists.)

But it is true that, along with many authentic works, there have been books or films which were only partly true, or even were partly faked. And unfortunately, even reputable historians often fail in their duty of care. For instance Martin Gilbert (biographer of Churchill) offers in Final Journey what is in many ways an admirably-presented resume of what happened to the European Jews.

But by quoting supposed 'eyewitnesses' who in fact are repeating hearsay, Gilbert perpetuates errors which—because they are so easily disproved—provide revisionists' opportunities. For instance, from his chapter 'The Treblinka Deathcamp': none of the 'Nazis in the camp … lived in the camp together' with their families; SS Hauptsturmfdhrer von Eupen was never commandant of Treblinka, but of the nearby training-camp Trawniki; the 'cries of the victims and the weeping of the children' could not be heard in the neighbouring villages, for with good reason the murderers ensured there were no villages within miles; and the Germans did not bring 'the most famous musicians in the world from the Warsaw ghetto' to 'play when the transports arrived'. There were such orchestras, for instance at Auschwitz, which played when the slave-labourers marched to and from work. But there was no need for such a thing at any pure extermination camp.

David Irving's Hitler's War falls into the category of 'partly true'. It had some interesting historical material, but sold (admirably) both here and overseas because of its bold and spurious claim that Hitler himself was largely unaware of the 'Final Solution'. Such books do better than, for example, Helen Fein's scholarly socio-history Accounting for Genocide, which is surely essential for any serious researcher. But this is an area in which commercially-motivated rubbish can have terrible long-term consequences.

'Personal' accounts, such as the recently-published Dora, heavily-publicised in the Guardian are not rubbish in themselves. Jean Michel, no doubt at all, was a labourer at the terrible slave-camp in the Harz Mountains where the V-weapons were built. The problem with books like this is that they are 'ghosted' by professional wordsmiths—the French are especially adept—who have neither interest in nor capacity for conveying truth with restraint. It is less the exaggerations than the false emphases and cheap humour which disqualify them.

Worse again are the partial or complete fakes, such as Jean Francois Steiner's Treblinka or Martin Gray's For Those I Loved. Steiner's book on the surface even seems right: he is a man of talent and conviction, and it is hard to know how he could go so wrong. But what he finally produced was a hodgepodge of truth and falsehood, libelling both the dead and the living. The original French book had to be withdrawn and reissued with all names changed. But it retained its format of imagined conversations and reactions—ie pure fiction—incredibly remaining, nonetheless, in serious bibliographies.

Gray's For Those I Loved was the work of Max Gallo the ghostwriter, who also produced Papillon. During the research for a Sunday Times inquiry into Gray's work, M. Gallo informed me coolly that he 'needed' a long chapter on Treblinka because the book required something strong for pulling in readers. When I myself told Gray, the 'author', that he had manifestly never been to, nor escaped from Treblinka, he finally asked, despairingly: 'But does it matter?' Wasn't the only thing that Treblinka did happen, that it should be written about, and that some Jews should be shown to have been heroic?

It happened, and indeed many Jews were heroes. But untruth always matters, and not just because it is unnecessary to lie when so much terrible truth is available. Every falsification, every error, every slick re-write job is an advantage to the neo-Nazis.

One other thing assists the revisionists: many Jews, including survivors from the Warsaw Ghetto and Treblinka, are unwilling to bear witness and expose people like Gray for what they are. Understandably, they do not wish to bring back their fearsome experiences into the lives they have rebuilt. Tragically, they fear renewed anti-semitism.

To return to Britain, now sadly enough a kind of neo-Nazi centre: who are the 'growing number of academic and public figures' whom Richard Verrall cites (NS Letters 21 September) as moving towards his position? I think David Irving's silly claim has been adequately dealt with in the Sunday Times, and he at least did not deny that the murders occurred.

The Australian lawyer John Bennett has been dealt with adequately by Ken Buckley (NS 5 October) and may be left to his fellow Australians. Robert Faurisson, an associate professor of Literature at Lyons, author of some light literary guides (As t'on lu Rimbaud etc) is certainly a study: I had a long telephone conversation with him recently in which he sought an urgent meeting with me, on the grounds that the 'artistry' of my work Into That Darkness had produced 'final proof that the gas-chambers never existed'. The mechanism of double-think is admittedly fascinating.

A principal authority for Verrall is Paul Rassinier, whose work has been well-described by Raul Hilberg as 'a mixture of error, fantasy and fabrication'. Rassinier, now dead, was a historian and was for a while imprisoned at Buchenwald. But neither of those facts place him necessarily on the side of the angels: when he sued for defamation a writer who said that he had made common cause with neo-Nazis, the allegation was found proved.

And the 'respected German historian Helmut Diwald' is in fact just that. His field, however, is the period from Charlemagne to Wallenstein (the Thirty Years' War), and when his Geschichte der Deutschen (History of the Germans) appeared early this year, his chapter on the Third Reich was almost universally found to be defective and incomplete. The publishers withdrew the book: issuing jointly with Diwald an apology and a promise that a new edition would deal 'unequivocally … with the persecution and murder of the Jews in the Third Reich'.

Finally, A. R. Butz, who is an associate professor of engineering at Northwestern University, Illinois. His Hoax of the Twentieth Century makes, as Hugh Trevor-Roper observed'a great parade of scholarship (but)…most of the book is irrelevant, and the central issue is evaded.' Northwestern's admirable response was to initiate, in the year Butz's tirade reached the US, first a course and then a summer school on their own campus, dealing with the facts of the holocaust. Always, the proper reply to these dishonourable men begins with knowledge.