Jim O’Neill, chief economist at Goldman Sachs, and Erik Berglof, his counterpart at the European Bank for Reconstruction and Development, said world leaders must embark on swift and coordinated action to stem the crisis that is engulfing the globe.

In interviews for the London Summit website they said that the outcome of the meeting of the 27 heads of state of EU countries had laid the groundwork for a consensus between Gordon Brown and Barack Obama at their meeting in Washington on 3 March.

They were speaking outside a workshop of economists and policymakers from across Europe organised by the Brussels think tank Bruegel and held at Lancaster House in Central London on 2 March.

Mr O’Neill praised the Prime Minister for getting a high profile meeting with Mr Obama, saying that the US would play a key role in resolving the crisis. 'I really admire the PM’s energy to get out there before the G20 because it is really important that the US realises the interest of other parts of the world in trying to make this meeting a big deal,' he said.

He said that with America just six weeks into a new administration, there would be a temptation to be a ‘little bit inward looking’ these sorts of intervention. 'Given how the US has played a critical role in the middle of this crisis, and in bringing us out of it, I am sure, I think the Prime Minister’s desire to get this meeting and push the G20 agenda is very impressive.'

He said he was encouraged by signs that European countries were looking to put their combined fiscal stimulus packages into the context of a stimulus for the world. 'That's what the rest of the world is going to be looking for from Europe so on that basis alone it’s pretty good. What we really need is more a collective realisation that unless we all act together we will all sink together,' he said.

Mr Berglof said that the current series of meetings was coming at a crucial time for Europe and the rest of the world. 'There is an enormous need for coordination and an enormous need for decisions that will deal with concerns on capital flows and on emerging markets in particular. It's very important to get this on the table and the London Summit offers a good opportunity to do that,' he said.

He said Gordon Brown’s priority in his meeting with Barack Obama was to get some focus on the G20 issues. 'As we know the United States is facing a lot of domestic challenges. [Brown's] challenge is to get this up on the radar screen in Washington. If he manages that, that will be very much a positive result of that trip.'