By Ross Hawkins
Political correspondent, BBC News
Gordon Brown: Will the G20 boost his domestic standing?
Welcoming world leaders to this summit, Gordon Brown looked every inch the happy host. He had good reason to be cheerful.
On Wednesday prime ministers and presidents walked up a red carpet to dine at his Downing Street table.
US President Barack Obama showered him in public praise
When the US and Russia said they would talk again about cutting their nuclear arsenals they did so at the "fringe" of
And the headline at the end of proceedings is one that will put smiles on the faces of those at Number 10 - one trillion dollars to tackle the economic crisis. The details may be complicated but the number is eye-catching.
Even the murmurs of discontent did little harm to the G20 meeting, or Mr Brown.
The threat from French President Nicolas Sarkozy to walk out if he did not get what he wanted added to the theatre of the occasion.
His joint press conference with German Chancellor Angela Merkel calling for tougher financial regulation assured onlookers there was still negotiating to be done.
Conservative leader David Cameron shared a little of the G20 stardust when he enjoyed a private meeting with Mr Obama.
But the television cameras recorded Mr Brown meeting the US president time after time, talking of one another on first name terms.
It is hardly surprising the British prime minister appeared to be enjoying himself.
Before the G20 he was dealing with altogether more squalid, parochial, unstatesman-like matters.
The worst of it was fending off questions about Home Secretary Jacqui Smith's expense claims for two blue movies watched by her husband.
The global economy faces rather more fundamental problems and trying to put them right looks a more dignified prime ministerial task.
For two days the mundane business of domestic politics has been put more or less on hold.
So much so that, when a Conservative MP called on the Treasury minister Lord Myners to resign at prime minister's questions, Mr Brown haughtily mocked him for failing to rise to the occasion of the London meeting.
He will not be able to laugh off questions like that for long.
Once the last motorcade has left, attention will turn to what this summit has achieved.
Mr Brown said the G20 leaders had to supply the "oxygen of confidence" to the global economy.
In the short term the markets will decide whether they have been successful or not.
The long-term verdict will come from voters. Pre-summit excitement left them with high expectations - not for the wording of a communique, but for measures which would help the British economy.
With European and council elections due in just a couple of months' time, and a general election by June next year at the latest, they will not have to wait long to voice their opinion.