Dr Iyad Allawi (58) the head of the Iraqi National Accord (INA), emerged as Iraq's surprise new leader after weeks of speculation and intrigue.
Earlier this year the INA said it had provided "in good faith" the raw intelligence from a single source that was used to support the now discredited claim that Saddam Hussein was able to deploy weapons of mass destruction within 45 minutes of the order. The INA said later it had presumed that MI6 would verify the 45-minute claim.
News of his appointment leaked out yesterday afternoon after Iraq's US-appointed governing council voted unanimously to recommend him as its choice.
Members of the governing council said Dr Allawi's knowledge of security and defence would be invaluable in the difficult months ahead.
"I think he is the best compromise candidate," Mr Mahmoud Othman, a leading member of the council, said. "Let's face it, security is our biggest headache. Dr Allawi knows the security issues. This will be a big plus."
Other observers were also enthusiastic. Mr Laith Kubba, a veteran Iraqi liberal who is now at the US-based National Endowment for Democracy, said Dr Allawi would be a unifying figure.
"It's a good choice. His credentials are very much a national Iraqi," Mr Kubba said. "He has reached out to Sunni and Shia as well as Kurds ... he can help rebuild national politics."
However, Dr Allawi's close links to US and British intelligence agencies will not make him a popular choice for many ordinary Iraqis.
With little sign of an end to Iraq's rampant insurgency, he now has an unenviable task - to try and nudge Iraq back to normality at a time when the coalition occupation is more hated than ever, and when most Iraqis are deeply sceptical of the UN-managed transition to democracy.
Having survived an assassination attempt in 1978, when Saddam's agents tried to hack him to death, his biggest challenge will arguably be to stay alive. Last week the president of Iraq's governing council, Izzedin Salim, another moderate, was killed by a suicide bomber.
The Iraqi resistance is likely to dismiss Dr Allawi as an American stooge and try to kill him. Either way, his tenure as prime minister will be brief, until elections next January when a new prime minister will be chosen.