2005 was the first election I watched. I desperately wanted Blair to lose his seat to the independent candidate who stood against him in Sedgefield (can’t remember his name, but he was the father of someone killed in Iraq), but Labour to win overall.
As for the war itself, there were massive public demonstrations at the time against it and there was a wholesome lack of conclusive proof that Saddam had WMD. I remember Colin Powell’s presentation of evidence to the UN which might as well have been a Cluedo board for all the proof it provided. The whole episode was utterly nefarious, yet provided one of the great Parliamentary speeches in modern times when Robin Cook resigned from the Cabinet.
I think a lot of people have used hindsight to claim they were against the war (which was initially fought on the basis of disarming Saddam, not regime change - that came about quietly when it was obvious there was nothing obvious to disarm him of), at the time I remember the usual suspects in the press being for it and some quite heated debates amongst friends at the time as to whether it was right or wrong to go to war.