Tony Blair has again defended the Iraq invasion, arguing the country is better off without Saddam Hussein.
The issue of the Iraq war keeps on reoccurring
The premier was asked about a memo of a meeting eight months before war when MI6 chief Sir Richard Dearlove said the US president saw action as inevitable.
Sir Richard added the intelligence and facts were being fixed around policy.
Mr Blair told MPs the memo had been covered by the Butler inquiry and that a UN resolution had been attained after the meeting and before the war.
The memo refers to a meeting in Downing Street on 23 July 2002 attended by Mr Blair, Attorney General Lord Goldsmith, Foreign Secretary Jack Straw, ex-defence secretary Geoff Hoon, Sir Richard, former head of the UK armed forces Admiral Lord Boyce and head of the Joint Intelligence Committee John Scarlett.
Sir Richard had just returned from talks in Washington and said "the intelligence and facts were being fixed around policy".
Mr Straw agreed it seemed clear George W Bush had made up his mind about military action but that the case for attacking Iraq was "thin".
"Saddam was not threatening his neighbours and his WMD capability was less than that of Libya, North Korea or Iran," he warned.
Mr Straw went on to suggest working up a plan to present Saddam Hussein with an ultimatum demanding he let in UN weapons inspectors or face military action.
Lord Goldsmith warned regime change was not a legal basis for military action though Mr Blair argued people would back removing Saddam if the political context was right.
The minute concluded: "We should work on the assumption that the UK would take part in any military action.
"CDS [Chief of Defence the Staff Lord Boyce] would send the prime minister full details of the proposed military campaign and possible UK contributions by the end of the week."
Mr Blair was asked about the memo during Prime Minister's Questions by Plaid Cymru MP Adam Price who has been calling for the premier's impeachment over the war.
Mr Price asked if Mr Blair regarded Sir Richard as being a "reliable source of information on Iraq" and if it was safe to assume that the MI6 chief's statement in 2002 was an accurate assessment of the US president's intentions.
Mr Blair replied: "This was of course before we went to the United Nations and secured a second resolution, Resolution 1441, that had unanimous support."
He went on: "Contrary to your view, when I stood next to the new prime minister of Iraq, somebody who had five of his relatives assassinated by Saddam, and realised that he was in power because of the democratic votes of eight million Iraqis, then I was glad that we took the action that we did and made sure that Iraq was no longer governed by a dictatorship but by a democracy."