Between American and Britain we have killed far more Iraqi nationals, and I would be surprised if our combined effect on the environment hasn't caused more damage than burning oil fields for months and destroying marshland. Calling the dead Iraqis (and our troops) causalities of war supposes that the war was legal - something I have yet to see proof of.
So who in the British and American administrations are going to swing with him?
Just what will we accomplish by hanging this man that we can't from a life in prison? what gives "us" the right to kill another - no matter what their crimes? are we not by definition murderers by killing him?