LONDON — Tony Blair may have swung behind US calls for regime change in Iraq after meeting President George W. Bush at his Texas ranch in 2002, a top diplomat told an inquiry into the war on Thursday.

Christopher Meyer, then Britain's ambassador to Washington, said Blair's line seemed to harden following talks at the Crawford ranch in April 2002, much of which were held in private with no advisors present.

He also detailed the warm personal relationship between the prime minister and US president, saying Bush could talk to Blair but saw other world leaders as "like creatures from outer space".

Blair strongly backed Bush, taking Britain into the US-led invasion of Iraq in 2003 despite lack of UN Security Council approval. He resigned in 2007, partly due to the unpopularity of the Iraq war.

The probe heard that toppling Iraqi president Saddam Hussein was not an early priority for Bush. Even after the September 11, 2001 attacks by Osama bin Laden's Al-Qaeda network, Saddam was merely a footnote.

Meyer, ambassador to the United States from 1997 to 2003, said he was "not entirely clear what degree of convergence was, if you like, signed in blood at the Crawford ranch."

But the day after, Blair made a speech in which he publicly mentioned regime change for the first time.

"What he was trying to do was to draw the lessons of 9/11 and apply them to the situation in Iraq which led -- I think not inadvertently but deliberately -- to a conflation of the threat posed by Osama bin Laden and Saddam Hussein.

"When I heard that speech, I thought that this represents a tightening of the UK/US alliance and a degree of convergence on the danger Saddam Hussein presented," he said.

Britain was still, though, encouraging Washington to act with the approval of the UN Security Council, Meyer said.

The US position at this stage was a significant change from the Bush administration's early days, when Iraq was seen as being like a "grumbling appendix", the retired diplomat added.

While there were concerns over Saddam, there were no plans to take action, despite calls from US hardliners like Deputy Defence Secretary Paul Wolfowitz, he said.

This changed after September 11. On the day of the attacks, Meyer spoke to Condoleezza Rice, then US national security advisor.

"She said: 'There's no doubt it's an Al-Qaeda operation' but at the end of the conversation, she said: 'We're just looking to see whether there could possibly be any connection with Saddam Hussein," he told the inquiry.

The following weekend there was a "big ding dong" -- a major dispute -- at Camp David, the US presidential retreat, when Wolfowitz "argued very strongly" for action against Iraq, according to Meyer.

But he added: "The decision taken that weekend was that the prime concern was with Al-Qaeda, it was with Al-Qaeda in Afghanistan, and Iraq... had to be set aside for the time being."

There was, though, a "fault line" emerging in the Bush administration between Secretary of State Colin Powell on one side and Vice President Dick Cheney and Defence Secretary Donald Rumsfeld on the other.

Talk of regime change in Iraq increased in the months before the Blair-Bush meeting at Crawford, Meyer said, adding that Britain's support was "taken for granted" by Washington.

The publication of Meyer's memoirs, "DC Confidential", in 2005, drew sharp criticism from some ministers and lawmakers who accused him of a lack of discretion, even though its released was approved by officials.

The inquiry, Britain's third related to the conflict, is looking at Britain's role in Iraq between 2001 and 2009, when nearly all its troops withdrew. It will report by the end of 2010.

Blair will give evidence in January.