As Fionn says, anyone who says what they believe on a matter over which there is no evidence, or where the evidence is prone to alternative interpretations, can justify themselves. But anyone who makes statements they know to be false has no such defense.

In Irving's case, if he'd just said that Hitler didn't know about the extermination of Jews, he'd be safe. Even though most people would reckon it's a safe bet he did, we don't have evidence one way or the other.

But he went and said that the extermination of Jews never happened. Now this is a statement that's so easy to disprove, it's beyond credibility that he could truly believe this. The only possible explanation is that he was lying, and this lying has successfully increased his bank balance over the years. In other words, like any other con artist, the only belief he's been imprisoned for is the belief that he could get away with it.

Graham.