Tony Blair and the pro-war parties and commentators have a single response to defend themselves against the accusation that the London bombings happened because he followed George W Bush into Iraq:
"9/11 and other Al Qaeda terrorist actions occurred before Iraq".
This is a sound defence against a hypothetical assertion that
"The invasion and occupation of Iraq is the sole reason for Al Qaeda's actions".
But nobody is making that assertion. The claim is that Blair's adventure in Iraq has made us a target of Al Qaeda's anger. There were no jihadist attacks on the UK homland prior to the 2003 invasion. Now here are. It is entirely reasonable to suppose that the London attacks would not have occurred if we did not have our troops on Muslim soil. Blair has to explain this.
As ever, the journalists and broadcasters are falling down in their duty of asking the tough questions of the Prime Minister. If anything, this is the worst aspect of it - the loss of a free press, the tail-between-the-legs, cringing attitude of the jornalistic profession.