To the question, "If the polls had shown you were leading in the key marginals and that there'd be a 100-seat majority for Labour, would you be calling an election?"

"I still would have made the same decision," he said. It's there on tape.

The air around him turned black, marsh gas bubbled sulphurously round his podium and when he opened his mouth, two tongues flickered out into the room. Or was it the E-numbers in my morning doughnuts? It's easy enough to say the Prime Minister's lying, but I have something more alarming.

These people need to believe they are truthful, honourable, moral. Such qualities are their most precious resources. A politician says something slightly untrue, a fib. The media sense it, the questioning intensifies and the politician ends up having to tell big, gob-stopping, full-fat lies. But because integrity is more valuable than sanity he adjusts himself to the lie; he rearranges his character around the lie so that he can say, "Whether I was right or not, I believed it to be the truth". Even now he may be persuading himself that the polls had nothing to do with his decision.

It's not that telling a lie makes you wicked, but believing your own lie makes you mad. You have to adjust the world to your own, false, version of it. And then you invade Iraq. How will it end for Gordon Brown? We'll have to wait and see.