"In the opinion of most, the war was an illegal and costly mistake which has made the world less safe and cost too high a price." – Gervase

Just to point out that just because that happens to be the opinion of most (It may, or may not be) does not necessarily make it true, or fact.

The threat posed by Iraq under Saddam Hussein to the United States of America, her allies in the middle-east and elsewhere and the interests of the United States of America and her allies, was not something invented and dreamt up by George W. Bush or any other member of his administration. The Head of State of any country does not require permission from anybody to act in the best interests of their nation's security, especially not such a weak and vacillating an organization as the United Nations.

"In your opinion the world is a safer place. I think you'll find yourself in rather a minority there." – Gervase.

Again only BB's opinion, but one shared after careful and independent studies by the University of Uppsala in Sweden and the University of British Columbia in Vancouver.

Now let's have a look at some of those quotations you saw fit to post:

""The war in Iraq ... has acted as a recruiting sergeant for extremists across the Muslim world ... Iraq has served to radicalise an already disillusioned youth and al-Qaeda has given them the will, intent, purpose and ideology to act."" – MOD Briefing Paper

"The Iraq conflict has become the cause celebre for jihadists, breeding a deep resentment of US involvement in the Muslim world and cultivating supporters for the global jihadist movement." - US National Intelligence Estimates

"a potent global recruitment pretext" for jihadists and says that the invasion "galvanised" al-Qaeda and "perversely inspired insurgent violence" there." - Institute for Strategic Studies

"the war in Iraq provided terrorists with "a training ground, a recruitment ground, the opportunity for enhancing technical skills... There is even, under the best scenario, over time, the likelihood that some of the jihadists who are not killed there will, in a sense, go home, wherever home is, and will therefore disperse to various other countries." - David Low, the US national intelligence officer for transnational threats.

"In the House of Commons in October 2003, before the invasion, Tony Blair himself said, "The assessment I received was that the greatest terrorist threat to Western interests came from al-Qaeda and related groups, and that this threat would be heightened by military action against Iraq...When I took the decision that military action would be required to ensure that Iraq complied with United Nations Security Council Resolutions, I had to weigh all the factors, including the possible short term risk of increased terrorism, against the longer term risks of rogue states developing weapons of mass destruction."
And we know all about the WMDs now, don't we?"

I note that you have only provided a date, albeit an incorrect one, for Blair (Well surely that must have been October 2002 as by the October 2003 the invasion was all done and dusted.) Now take a look at what came of those dire predictions Gervase:

•        Heard anything of Al-Qaeda-in-Iraq lately??
•        Heard anything of Al-Qaeda full stop lately??
•        In Iraq the Islamic Jihadists were drawn into fighting battles not of their choosing and they have died in their thousands
•        In Afghanistan the Taleban have died in their thousands and are viewing the prospect of annihilation if they continue to confront the forces ranged against them

The quote and prediction above from David Low was made on the premise that the Jihadists would be victorious – they weren't, they died in places like Fallujah and other places in Anbar and Diyalla Provinces.