LAURENCE REES: If there’s one thing that you would want people who study this period to take from it, what would it be?

SIR IAN KERSHAW: I suppose a sense of the momentous nature of these events in Europe, which will never be repeated, because we can’t fight a war like that ever again. And you think of the absolutely phenomenal numbers of people who lost their lives in this conflict, the extent of that conflagration which is greater than even the First World War and any other war in history.

So you’ve got the greatest war in history here, and it’s a war which determined in many ways the shape of the 20th Century that followed it. The forty years of the Cold War were actually the follow-up to the Second World War and we are still seeing, in a way, the ramifications of that war even now that the Cold War is over.

So, I think it’s not just looking for this point or that point in it, but the war as an entity, a war which was a genocidal war, as a central component of it. And the notion of the horror of what human beings can do to each other, but this was horror on a scale that’s never before been experienced and which then determined the shape of the rest of the 20th Century. Our own lives would be so different if we didn’t have this war there, from which many of the things that we understand have actually flowed.