From the minutes of the July 23, 2002 UK Prime Minister’s meeting:

C reported on his recent talks in Washington. There was a perceptible shift in attitude. Military action was now seen as inevitable. Bush wanted to remove Saddam, through military action, justified by the conjunction of terrorism and WMD. But the intelligence and facts were being fixed around the policy. The NSC had no patience with the UN route, and no enthusiasm for publishing material on the Iraqi regime’s record. There was little discussion in Washington of the aftermath after military action.

And:

It seemed clear that Bush had made up his mind to take military action, even if the timing was not yet decided. But the case was thin. Saddam was not threatening his neighbours, and his WMD capability was less than that of Libya, North Korea or Iran. We should work up a plan for an ultimatum to Saddam to allow back in the UN weapons inspectors. This would also help with the legal justification for the use of force.