Rupert Cornwell: Roles are reversed as 'George and Tony' show nears its end

It was supposed to be, as the Downing Street and White House jargon has it, a "forward-leaning" meeting, dwelling on the future of Iraq and Iran and the irresistible march of freedom and democracy to the darkest recesses of the planet. In the event, the joint press conference of George Bush and Tony Blair was a rather sorry affair, less sunlit uplands of the future than the dark valleys of the past. Just like their respective intelligence communities, these two leaders have a credibility problem, reflected in their abysmal opinion poll ratings. On Thursday evening, it showed.

Mr Blair was as usual fluent but - at least to this observer, who sees him only rarely in the flesh - without the usual self assurance. He was a curiously diminished figure, thinner, greyer and above all more vulnerable. Usually it is the Prime Minister who rides to the rescue of this President, whose tongue-tied swagger so grates on foreign sensibilities, but to whom Mr Blair has chained his political fate.

But on this his eighth post-9/11 visit to Washington, the roles were sometimes reversed. As usual, as Mr Bush wallowed in his linguistic morass of "deciders", and "suiciders" and "Aboo Geraib" (Abu Ghraib), Mr Blair provided the linguistic polish. But in this instalment of the "George and Tony" show, the President on occasion came to the rescue of his trustiest friend. Was this an occasion to say farewell, given that this might be the last such of its kind, a British reporter inquired? For once, Mr Blair seemed lost for words. But pal George smartly stepped in.

"Don't count him out," the President said, having just praised Mr Blair's resilience and constancy. "I want him to be here so long as I'm President," he added, oblivious to the concerns of Gordon Brown, for whom sometime in 2007 - or sooner - rather than 20 January 2009, is the desired moment of hand-over in Downing Street.

But above all, it was a time of confessions, and the acknowledgement of mistakes. For Mr Blair, the big error was de-Baathification - the reckless dismantling of the Saddamist bureaucratic infrastructure ordered in 2003 by the hapless proconsul Paul Bremer (now rewarded with the Presidential Medal of Freedom).

For Mr Bush, as usual, admitting error was like having a wisdom tooth removed without anaesthetic. But some mistakes he did concede: not least the Texan macho talk of "Bring 'em on" and "Wanted dead or alive" - "I learnt some lessons about expressing myself in a little more sophisticated manner."

But the worst was the disclosure in April 2004 of the prison abuse photos at Abu Ghraib: "We've been paying for that for a long time."

Mr Blair listened intently. Looking at our aged and drained Prime Minister, you could not but ask yourself whether there are moments in the small hours when he asks himself, was Iraq the most terrible mistake? If so, the moment surely passes quickly. But on Thursday, he was a prisoner of the past.