LAURENCE REES: But the American army is made up to a large extent of farm boys from places like Idaho and Omaha and they’re also growing up slitting open pigs on farms, but they’re not coming at the war in this kind of way, are they?

DAVID CESARANI: Aren’t they?

LAURENCE REES: You think not?

DAVID CESARANI: There’s a great scene 20 minutes into Saving Private Ryan when the Ranger Unit gets to the top of the cliffs and there are various Germans trying to surrender and they gun them down. This is really off the point but I think one of the merits of Antony Beevor’s D Day book is that he doesn’t pull any punches. Certainly in a conflict between the Canadian Division and Hitlerjugend Division they just slaughtered their prisoners. And from what I know in many engagements that the American Army fought in Normandy, certainly at the time of the Battle of The Bulge and thereafter, they didn’t always take prisoners. We are expecting too much of our fighting men and women. Then and now.

And this is really off the point, although it is in some ways relevant. I get so irritated by the holy outrage over things like our boys in Basra killing prisoners, I mean, what do you expect, really? These are young lads who have been trained to kill - I think we’ve had this conversation before, actually - and they don’t come from peasant backgrounds any more, you know, they come from Luton and Newcastle but they join the army when they’re 16, 17, 18, they come in as teenage soldiers. All they know is violence and killing and a kind of macho culture, and you put then in an environment in which they’re stepping over corpses, wading through pools of blood, their friends, their officers who they love and trust are being killed and blown up and they get their hands on a 'rag-head', someone who’s been dehumanised in propaganda, who they have a racist inclination towards, and they 'pop' them. And of course it’s terrible, it’s murder and it should not happen, but when it does happen I just can’t believe that the Guardian and its readers get so upset.

LAURENCE REES: Well, perhaps they should still be upset but not surprised.

DAVID CESARANI: No, I don’t think they should even be upset. I think they should just be very businesslike about it…

LAURENCE REES: Well, it’s a crime…

DAVID CESARANI: Of course it’s a crime and military policemen who investigate these things go, 'Oh my God, they killed a prisoner!' They say let’s get the evidence and prosecute the guy. And that is one reason why the military has traditionally always insisted that military judges should judge men from the ranks who commit crimes. The armed services always insist that the only way you can understand the psychology of soldiers is if you are yourself a soldier, and you therefore do not have double standards, you understand the emotions, the psychology that runs through the minds of these people. You cannot have civilians judging soldiers, it’s a very controversial point of view, but I think it has great traction and I appreciate it.

LAURENCE REES: Would you agree that the thing about the Second World War is it shows - as one veteran put it to me - 'we were better than they were'?

DAVID CESARANI: Well, we were better than they were because we were defending democracy, more or less, civil rights, more or less, we did have more compassion than they did most of the time, though that didn’t stop us bombing their cities to rubble. We were better than they were on the whole. Arthur Koestler put it very, very well. The Second World War’s a case of fighting a whole lie in the name of a whole half-truth, and sometimes a half-truth’s better than none at all.