Obama flies in to fortress London | Brown urges world leaders to unite | G20 leaders, police and protesters ready as summit comes to town | Jamie Oliver cooks for the G20 | City of London braces itself | Time to reset capitalism's moral compass | Valentine Low: Sketch | Ann Treneman: Sketch

Waving a last goodbye to the cameras at Santiago, Gordon Brown was shown to his quarters in the Boeing 747 on Saturday. But as others relaxed after the rigours of a six-day world tour, he could be seen hunched over a copy of his address to St Paul's Cathedral, his black marker pen stabbing the paper.

Close at hand were Stewart Wood, a foreign policy adviser and one of the summit’s “sherpas”, and Tom Fletcher, his most senior civil servant advising on foreign affairs. Lord Mandelson, a man whom Mr Brown acknowledges as Labour’s best strategist, was barely a brace of business class seats away.

This speech, however, was not to be a collaborative effort. From Adam Smith to Abraham Lincoln, it was nothing less than an argument for the resetting of capitalism’s moral compass – an exposition of everything he hoped to achieve at the G20 meeting.

Mr Brown told his audience that Smith “came from my home town of Kirkcaldy” but his closest allies discourage the suggestion that he believes himself chosen by fate.

They do not deny, however, that he has become consumed by the preparations for the summit. In recent weeks the Prime Minister has been seen much less often in the open-plan “war room” in No 12 Downing Street. Whether travelling abroad or in his study at No 10, he is rarely off the phone.

“It’s an endless, rolling series of talks.” one close adviser said last night. Another said: “I’m not sure he personally is getting a buzz from it all, even if some of those around him are – this is what Gordon does, grinding a deal out.”

In his speech yesterday, Mr Brown appeared to acknowledge that voters may not be impressed by a new deal on trade finance or action on tax havens. “The most important financial summits are those that take place around their kitchen table,” he said.

While Mr Brown is being careful not to appear too thrilled at assembling 28 world leaders for a meeting in London, his guests are not so shy about trumpeting the achievement. In a private meeting with Labour MPs, Kevin Rudd, the Australian Prime Minister, said that Mr Brown had both the “intellectual capacity” to understand the problems and the “political gifts” to reach a deal on a solution. “We’re only here because of him. He’s made all this happen,” he said.

Although even Downing Street acknowledges that expectations were allowed to run ahead of what could be delivered, few would deny Mr Brown’s success in elevating what was once a routine meeting of finance ministers into a blue-ribbon event of summitry.

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