In an ideal world, it would not take a film star to get the media focused on mental illness.

My closest friend, who died not long ago, is buried near Marx's grave in Highgate cemetery, so I see the gaggle of admirers laying roses at the foot of his tombstone regularly. I have never been tempted to leave flowers there myself. Great theories, shame about the practice. Marx did many things. But inventing class was not one of them.

My aunty says I'm the double of my father. He was a workaholic, which I've definitely inherited. And like me, he could be the life and soul of the party, but also quite withdrawn.

Friends have suggested that I am the least qualified person to talk about happiness, because I am often down, and sometimes profoundly depressed. But I think that's where my qualification comes from. Because to know happiness, it helps to know unhappiness.

Tony's [Blair] convinced I'm going to find God. I do have spiritual moments, but I don't think it's God.

I do think it's strange that I get associated with Iraq more than the people who were Foreign Secretary or Defence Secretary. It's because of my closeness to Tony [Blair], which I don't regret at all. I think that was a privilege.

Sometimes Jonathan [Powell] and myself would go to Tony [Blair] and ask him if he was absolutely sure about this or that. That was our job. But ultimately it was his decision.