It isn't enough to watch a film about the Holocaust. You need to see for yourself.

No doubt many readers will recall the trial; my peers who were barely teenagers then will not. And for that, Denial is a valuable reminder that the debate about what the Nazis were capable of and culpable for did not end with Auschwitz’s liberation. Out this month, it’s vital viewing, not least for the scene in which the British Jewish community is shamefully depicted asking the American upstart not to make waves.

Most moving is an extended scene in Birkenau, when Lipstadt recites Kaddish, the lyrics poetic and haunting against the desolation. It’s a trip I made as a student, and I remember being thoroughly moved by that same act; Jews commemorating the dead in the proper way, precisely where they tried to destroy us. Over a freezing weekend, we young Jews from Britain and South Africa walked around concentration camps and ghettos (or their remains); Auschwitz, Majdanek, Płaszów, Warsaw. Places that spoke of unimaginable tragedy, but also of survival.

A few years earlier I’d travelled around Eastern Europe, visiting Berlin, Budapest, Prague; seeing firsthand the cities where Jewish communities had once thrived, and visiting Theresienstadt, where Red Cross emissaries were reassured by the Nazis’ propaganda efforts.

These were places, stories, history, familiar to me from page and screen, and yet not familiar at all. Krakow, for example, was immortalised in Schindler’s List. But seeing the town’s old shuls and standing in the square where Jews were ghettoised 66 years later made it real in a way a book or film never could.

It’s trite, perhaps, to say you can’t appreciate the magnitude of the Holocaust without seeing those gates, the piles of shoes, the suitcases with addresses on them. That you can’t grasp six million until you stand on the train tracks or before the remains of a gas chamber; until you step where Nazis murdered Jews because they could. That you can’t begin to comprehend a death march until you are at a concentration camp on a snowy day, wrapped up warmly and still shivering, a coach waiting nearby.

Trite, perhaps, but not untrue. You can see some of this in museums, but museums confine what happened to the past, rather than confronting you with an open wound. There is simply no comparison with seeing it for yourself.

So while the books and films about the Holocaust contribute enormously to our understanding — and they do, both those that are testimony and those that use fictional stories to illuminate real ones — they are only part of the puzzle.

That’s especially so now, with fewer survivors to recall what happened, when with a quick Google we can open ourselves to more misinformation than Irving could ever have dreamed of. When “fake news” is drowning out hard facts, and the pernicious values that led to Denial are resurgent. It’s terrifyingly easy for someone to discredit a film, to dismiss a true account for exaggeration or bias. Seeing something firsthand may not be a foolproof response, but it’s the best we have.

In 2017, with cheap flights to Europe and a generational travel bug, there’s little excuse for young Jews — indeed, young non-Jews — not to see it for ourselves. Not to make us feel guilty or blackmail us into caring about Judaism or convince us that antisemitism is real. Simply to impress upon us what happened, so that we can carry on telling the story with authority. So that in another generation, we are still able to take on the Irvings of this world.