The US was “hell bent” on a 2003 military invasion of Iraq and actively undermined efforts by Britain to win international authorization for the war, a former British diplomat told an inquiry. Jeremy Greenstock, British ambassador to the United Nations from 1998 to 2003, said Friday that President George W. Bush had no real interest in attempts to agree on a UN resolution to provide explicit backing for the conflict. The ex-diplomat, who served as Britain's envoy in Iraq after the invasion, said serious preparations for the war had begun in early 2002 and took on an unstoppable momentum. As diplomats frantically attempted in early 2003 to agree upon a UN resolution approving a military offensive, Bush's key aides grew impatient – criticizing the process as an unnecessary distraction, he said. Grumbling from Washington “included noises about ‘this is a waste of time, what we need is regime change, why are we bothering with this, we must sweep this aside and do what's going to have to be done anyway - and deal with this with the use of force,”' Greenstock testified before the inquiry into the Iraq war. Several nations had hoped to stall the invasion of Iraq to allow UN weapons inspectors more time to search for evidence that Iraq had weapons of mass destruction - the key justification for the war. No such weapons were ever found. Yet Bush's inner circle cared little about what international allies thought and refused to halt plans to invade in March 2003, Greenstock said. He said even Blair was unable to persuade Bush, winning only a brief hiatus of two weeks. “The momentum for earlier action in the United States was much too strong for us to counter,” Greenstock said in a written statement to the inquiry, provided alongside his live testimony. Britain's inquiry is the most exhaustive study yet into the war and will seek evidence from former Prime Minister Tony Blair, military officials and spy agency chiefs. It won't apportion blame or establish criminal or civil liability. But it will offer recommendations by late 2010 on how to prevent mistakes from being repeated in the future. Greenstock told the five-person inquiry panel that the failure to win UN approval for the war had seriously undermined the legitimacy of the conflict. He said, in his opinion, the US-led invasion of Iraq was legal – a view rejected by critics who say it violated international law – but was of “questionable legitimacy.”