When it was announced that I would be making a BBC documentary about Holocaust denial, most people had one question: why give these people the airtime? It’s a fair one – one I had wrangled with in my own mind long before agreeing to sit opposite anyone who might undermine the truth of an atrocity which killed millions, my own family included. The need to make the film, however, is evident from the statistics: one in six people globally either don’t believe the Holocaust happened, or that the numbers have been exaggerated. The film tries to deconstruct why this conspiracy theory has persisted, by charting its roots in the Second World War, its present forms in Eastern Europe and the Middle East, and unpicking the strange logic by which Facebook allows posts on the subject on its platform. But also, there was a sense that to really get to the bottom of this, I should meet deniers. It was a difficult quandary. In the film, I talk to Anthony Julius, the lawyer who successfully represented historian Deborah Lipstadt when she was sued by David Irving for claiming he was a Holocaust denier in the 1990s. His view is simple: why not just ignore them? Well, partly because this is a documentary about what is unfortunately a growing phenomenon, and also because the landscape, in my opinion, is different now to when that highly publicised Irving trial took place. Now, for better or worse – really, for worse or worse – deniers have airtime: just not on screens like the BBC Two one on which you can see Anthony Julius and I discussing whether or not to give them airtime. As a historian of denial, Deborah Lipstadt has one rule of thumb: you do not debate the facts of the Holocaust. I agree. If I was going to meet a denier, it would be to try and understand why anyone would want to fly in the face of one of the most well-documented events in history. It would not be to have an argument about whether or not Auschwitz was in fact an internment camp in which some people unfortunately died of typhus. But how could I be sure that such a meeting would not become that argument? As the film went on, and I learnt more about the ways in which the truth of the Holocaust has been attacked over the years, including the way British propaganda deliberately left out information about anti-Semitic Nazi atrocities during the war, I became increasingly unhappy about the idea of meeting a denier. My grandparents and my mother were refugees to this country, and they only just got out of Germany, on effectively the last boat, in 1939. Most of their – my – extended family were murdered. The truth of the Holocaust lives in my here-by-the-skin-of-my-teeth bones. I find the idea of someone telling me that all that is a lie not just offensive, but obscene. Plus I’m not Louis Theroux, with his extraordinary ability to remain unreactive in the face of terrible opinion. I worried that if I was to come face to face with a denier, I might end up in an actual fist fight. But as we continued to film, I couldn’t shake the feeling that I should meet at least one, no matter how uncomfortable the idea made me. Because I was trying to get under the skin of this monster: and at the end of the day, that probably involves meeting the monster. Or at least one of its disciples. By now, I had been contacted online by a number of deniers who knew that I was researching the subject, and were very keen to speak to me. The image that people have of a Holocaust denier is possibly still defined by Irving: that of a professorial type, in a suit and tie – someone who went down that road of untruth and anti-Semitism, but preferred to dress it up as history. They still exist, but are vastly overwhelmed now by internet trolls, who use Holocaust denial not as a fake history, but just as a way of provoking and causing offence for the hell of it. One of the people who got in touch was an Irishman, called Dermot Mulqueen. He lives in Ennis, in Country Clare, and in 2015 was arrested after putting an axe through a TV in the main square, in protest at Holocaust Memorial Day. He was keen to meet. I looked at his Facebook page. It has much fake history on it and, like Irving, he offers to take people on “alternative” tours of Auschwitz. But there are also many, many of the hideous denial memes you’ll see on modern trolls’ sites. Dermot seemed to me the perfect storm of where Holocaust denial is now. Which is a strange sentence to write, but there you are. I went to Ennis to meet him. I was nervous, much more than I normally am doing TV. To see how it pans out you will have to watch the film, but I can tell you it isn’t a calm, polite conversation. Nor do I do that well in sticking to my resolution of not debating the facts of the Holocaust. Due to some of the extraordinary claims Dermot makes, I did find myself falling back on comedy: at one point he insists that Jews run the BBC, to which I reply, “I promise you if Jews ran the BBC, I’d be on it more.” If you want some sense of the whole thing, know that I hadn’t had a drink in 18 months beforehand, and straight after, downed a Guinness in one. However traumatic our encounter was, when I watch the whole film now I am confident it was worth meeting Dermot Mulqueen – the penultimate interview before one with a survivor, Rachel Levy. Her story, her testimony, would always be extremely moving, but there is something about hearing it immediately after Dermot’s ridiculous slurs that makes it all the more powerful. The truth – not just of the Holocaust, but all truth – is under attack more now than ever before, as technology allows anyone who wishes to create their own versions of history, and it is hard for those of us who deeply believe in truth to know exactly how to preserve it. Perhaps it is indeed better to ignore fake newsmongers and conspiracy theorists in all forms. But when I watch this film, I feel how much stronger the truth is for acknowledging the lie. Confronting Holocaust Denial with David Baddiel is on Monday 17 February at 9pm on BBC Two. David Baddiel is also on a UK tour with his new one-man comedy show, Trolls: Not The Dolls – all dates at davidbaddiel.com