..but you have to look holistically. Not going in meant more of the murderous Saddam regime. He would have continued to ethnically cleanse certain parts of his population, put others under brutal control and tortured and murdered them. He would have been in charge as the Arab Spring arrived and we all know that dictators and a movement like the arab spring means massive bloodshed.
Did he make a mistake going in yes, was there reason to get Saddam out yes. It's not as black and white as the red tops would have everyone believe....and just for the record, the next 3 Tory PMs all voted to go to invade Iraq. He was implementing Parliamentary decision, so Cameron, May and Boris are equally war criminals.