A comment on legality.
I was serving in the Armed Forces until early 2003. A very good friend of mine was posted as a senior planner in HQ 3 Commando Brigade at the time. In mid-2002 his brigade was involved in detailed preparation (not just planning) for the invasion and occupation of Iraq.
I don't know how much knowledge you have about deploying large ground, air and naval assets to a war zone, but it is a very expensive business. This preparation was costing the British taxpayer many millions and is a clear expression of intent. Discussion at the time was never framed in terms of "if we go in" but rather "when we go in, in spring 03".
Any subsequent fumbling for legitimacy was complete window-dressing. The decision had been made long before.
Anecdotal? Surely. But as clear indication that minds had been made up about timescale? Definitely. From a military perspective the attack on Iraq had to take place when it did - any later in the year and various natural elements would have made things vastly more difficult. There is no way in the world that Bush/Blair would have left tens of 1000s of troops in the Middle East for months. No way at all.
They put huge amounts of pressure on all other agencies to secure a legal pretext and failed. What to do?
Oh, yeah. Invade anyway.
Keeping what you've just read in mind, now read what British Prime Minister Tony Blair had to say to the House of Commons on 25th February 2003:
"Even now today we are offering Saddam the prospect of voluntary disarmament through the UN. I detest his regime. But even now he can save it by complying with the UN's demand."
And now ask yourself: what sort of world are we living in, when the man who told such a brazen, shameless lie, which led to a war which was claimed the lives of nearly 1m people, is not facing a trial for war crimes, but trying to rake in £8m for the sale of his autobiography?