I still don't think Blair intentionally lied to the country.
Neither do I.
I think he was basically took to the cleaners by the USA, he simply didn't see them lying to him and was sucked in big style.
The UN were quite happy for Blair to keep hold of Bush's leash after 9/11, and because Blair had to do that, he was seen as the man to sort it all out, well at least provide the legal standing to enter Iraq.
Blair basically said to Bush, you need proof or you cant go storming in, within a couple of months Bush had his proof, and Blair either had to back off and let a strong ally go on without him, or stand shoulder to shoulder and hope for the best, he went in with the USA not knowing all the WMD proof was all bullshit, it really has cost him his job and up until then, very good reputation both home and abroad.
Blair was bitch whipped by the US and Bush, he thought British politics was sneaky, but he didn't have a clue what comes out of the USA.