He's said something about it on the fly, anyway:
Discussing his decision to deploy British troops based on the threat posed by Saddam in the wake of the September 11th terrorist attacks, Mr Blair said: "I was not prepared to run the risk, and Parliament backed me." [Emphasis added.]
It would be interesting to hear from some of those who overlook the significance of this point what they think would have happened had Parliament not backed him.
Update. The report under the link has been edited, and the phrase I put in bold removed. But Blair did say that. He also said: 'I had to take the decision. I believed, and in the end the Cabinet believed - so did Parliament incidentally - that we were right not to run that risk.'