By Bridget Kendall
Diplomat correspondent, BBC News
Did the French and German leaders' comments help the G20 summit out?
One of the arts of summitry is never to raise expectations too high.
At the start of this week, there was a whiff of concern among some of those involved in government PR that perhaps public anticipation had sunk so low, it would be hard to sell the G20 outcome as anything other than pointless.
Then along came President Nicolas Sarkozy, with his threat of a boycott and the press conference which he and Angela Merkel staged upon their arrival in London.
On the face of it, a piece of brazen Gallic cheek - to upstage your host and threaten to sabotage his big moment.
But it turned out that he and Chancellor Merkel did Gordon Brown and the entire G20 summit a favour.
It was to be expected that Gordon Brown would talk up his own summit's achievements. And no surprise that President Barack Obama would want his first major foreign trip launched with a successful example of global collaboration.
The real historic significance of this moment may be the historic shift it marks - away from Western dominance to something bigger and more global
But when the sceptical French and German leaders emerged to declare that the final communique's crackdown on tax havens and tighter financial regulation had been a triumph and a historic compromise had been achieved, their enthusiasm seemed to carry extra weight.
Now, it is easy to take that thought a step further and conclude the entire spat must have been fabricated. But it is important on these occasions not to succumb to the temptation of conspiracy theories.
Outcomes of summits are by no means preordained. Genuine relief that the meeting was able to agree upon a convincing final document seemed to come from across the board.
There is often real tension and disagreement. And this time too, it seems, there was plenty of room for the consensus to falter.
Mr Sarkozy - for example - noted that a last minute logjam was only cleared when Mr Obama intervened to persuade China's President Hu Jintao - concerned at the implications for Macao and perhaps Hong Kong - that naming and shaming blacklisted tax havens would be a good idea.
In more stable times, it may well be that this large baggy grouping will be rather more difficult to manage
Not everyone around that enormous conference table could have made their voices easily heard at those plenary sessions, where they went through the draft communique, paragraph by paragraph.
From the brief glimpse we were granted, it looked like a somewhat cumbersome, awkward event, as though the dour British prime minister was presiding over the scrutiny of the text in the guise of a parson in a rather strict Bible study class.
Yet the concerns of many, it seems, were taken into account.
China secured a pledge that within the next two years the old rule would be scrapped that decreed only an American and European could head the top two financial organisations, the World Bank and the IMF.
The South African president noted there had been a real recognition that developing nations did not just need help but offered an opportunity for growth.
And Russia's Dmitry Medvedev, though he got no chance to present his pet project of a super currency, also seemed well pleased.
"I am almost tempted to say it was a turning point - except that would be irresponsible," he declared with the typical pedantry of a Russian lawyer at his final press conference.
But there is another aspect of this summit which is important.
Whatever the impact of the action plan, the real historic significance of this moment may be the historic shift it marks - away from Western dominance to something bigger and more global.
Group photo: Spot which world leader is missing
The G8 grouping will no doubt continue. The intimacy of eight or so leaders who can talk informally round a small table cannot be recreated here. But this gathering serves another purpose and it marks a coming-of-age of another way of looking at world politics.
There will be plenty of challenges for those who host its meetings. On occasion it can clearly be like herding cats. Look at the mix-up over the group photo.
First they take the portrait and realise Stephen Harper, the Canadian prime minister, is missing. Then, good-naturedly, they all gather to do it again and leave out Silvio Berlusconi of Italy.
And on both occasions, they fail to notice: there are simply too many leaders, it seems, to take them all into account at any one gathering.
Or perhaps these are too many big political egos to be kept waiting on a set of steps while officials count and check the line-up. How do you prevent some two dozen powerful leaders, all of them used to being the ones that make the decisions and lead from the front, from wandering off in different directions?
Channelling the collective G20 mind towards one goal may work when a crisis is pressing and alarming, as now.
In more stable times, it may well be that this large baggy grouping will be rather more difficult to manage, even if it is how the international community will define and tackle global priorities in the future.