This might have made sense in 2001, but in 2007 it's more of a stretch. Blair could presumably say whatever he wants to say now. The US hardly in a position to attempt a hatchet job on the UK economy, so he could easily have come out and thrown Bush off the cliff. This would be the honourable thing to do now, and is probably the only way Blair can redeem himself.

My guess is either some other form of blackmail - Blair's background is unlikely to be completely squeaky clean, and a few whiffs of weed would be enough to do him seriously political damage - or that Blair got religion in a serious way and actually believes he's in a crusade against Islam.

Or possibly both.

I've seen speculations that the US has a stack of kiddy porn leads on UK pols - which is sort of plausible, but only in a mad conspiracy theory kind of a way. It makes as much sense as any other explanation - which is to say, not much sense at all.

If Bush goes down, Blair would finally be able to tell all - at least subject to the usual threats of a nasty accident. Since an autobiography is inevitable, that would be the obvious place to tell the full story.

But my guess is that whatever the secret is, it's going to stay with Blair until he's dead and buried. And it's likely we'll never know for sure.