Mr Blair is due to have talks with Iraqi President Jalal Talabani and Prime Minister Nouri Maliki to discuss how to push for greater political reconciliation in a country fractured by sectarian violence.

His decision to join US President George W. Bush and send British troops to topple Saddam Hussein in 2003 despite huge opposition at home was the defining moment of his rule.

He decided to cut short his third term, and will quit on June 27. Finance minister Gordon Brown will take over.

Four years after the invasion, US and British forces face daily attacks from insurgents, sectarian violence is undermining the state and officials within and outside Maliki's coalition admit stabilizing Iraq is almost a “mission impossible”.

But Mr Blair believes there have been positive political developments and he wants to discuss a coherent plan with Mr Maliki to see faster progress.