There is no constitutional requirement for the Crown to seek any explicit form of parliamentary approval before committing British forces to military action.
However the political controversy over whether to participate in military action, which covered the legal legitimacy as well as foreign policy questions, had been under discussion for many years.
Finally, on 17 March 2003, US President Bush gave an ultimatum to Saddam Hussein to leave power within 48 hours or face military action.
The government proposed a motion in Parliament, stating: This House notes its decisions of 25 November 2002 and 26 February 2003 to endorse UN Security Council Resolution 1441; recognises that Iraq's weapons of mass destruction and long range missiles, and its continuing non-compliance with Security Council Resolutions, pose a threat to international peace and security; notes that in the 130 days since Resolution 1441 was adopted Iraq has not co-operated actively, unconditionally and immediately with the weapons inspectors, and has rejected the final opportunity to comply and is in further material breach of its obligations under successive mandatory UN Security Council Resolutions; regrets that despite sustained diplomatic effort by Her Majesty's Government it has not proved possible to secure a second Resolution in the UN because one Permanent Member of the Security Council made plain in public its intention to use its veto whatever the circumstances; notes the opinion of the Attorney General that, Iraq having failed to comply and Iraq being at the time of Resolution 1441 and continuing to be in material breach, the authority to use force under Resolution 678 has revived and so continues today; believes that the United Kingdom must uphold the authority of the United Nations as set out in Resolution 1441 and many Resolutions preceding it, and therefore supports the decision of Her Majesty's Government that the United Kingdom should use all means necessary to ensure the disarmament of Iraq's weapons of mass destruction; offers wholehearted support to the men and women of Her Majesty's Armed Forces now on duty in the Middle East; in the event of military operations requires that, on an urgent basis, the United Kingdom should seek a new Security Council Resolution that would affirm Iraq's territorial integrity, ensure rapid delivery of humanitarian relief, allow for the earliest possible lifting of UN sanctions, an international reconstruction programme, and the use of all oil revenues for the benefit of the Iraqi people and endorse an appropriate post-conflict administration for Iraq, leading to a representative government which upholds human rights and the rule of law for all Iraqis; and also welcomes the imminent publication of the Quartet's roadmap as a significant step to bringing a just and lasting peace settlement between Israelis and Palestinians and for the wider Middle East region, and endorses the role of Her Majesty's Government in actively working for peace between Israel and Palestine.
It removed the text "recognises that Iraq's weapons ... in the Middle East" and replaced it with: This House... believes that the case for war against Iraq has not yet been established, especially given the absence of specific United Nations authorisation; but, in the event that hostilities do commence, pledges its total support for the British forces engaged in the Middle East, expresses its admiration for their courage, skill and devotion to duty, and hopes that their tasks will be swiftly concluded with minimal casualties on all sides... Parliament voted on the amended text in a vote at 9:15 pm, but the amendment was defeated by 396 to 217 votes.