By politics.co.uk staff
David Cameron has arrived in Canada for the G8 summit, having written an article criticising international summits as "grand talking shops".
Political leaders are arriving in Ontario for the summit today, to be followed by G20 leaders for a wider conference dealing with economic issues over the weekend.
Describing himself as the "new kid on the block", Mr Cameron wrote an article in Canada's Globe and Mail newspaper saying international summits often "fail to live up to the hype and the promises made".
He went on: "I'm sure other leaders would admit that. A lot of money is spent laying them on. Host cities are disrupted for days or even weeks. Good intentions are shared in productive talks. Then, somehow, those intentions rarely seem to come to fruition in real, tangible global action. When we meet again a year later, we find things haven't really moved on.
"So the challenge for the upcoming G8 and G20 is to be more than just grand talking shops."
But the new prime minister also appeared to dampen expectations, particularly in relation to the Doha trade round at the World Trade Organisation (WTO), which aims to lower international trade barriers.
"I'm realistic," Mr Cameron wrote.
"Delivering progress on Doha will not be easy. However, I'm also impatient for change and people in Britain, Canada, Asia, Africa and elsewhere can't wait for negotiators to come to agreement.
"World leaders have made previous commitments on Doha in good faith - but despite almost a decade of talks, there's been no breakthrough."
The comments come as America pursues a markedly different economic agenda to most other world powers.
Once internationally isolated, Mr Cameron's fiscal conservatism now constitutes something akin to a consensus among world powers, and president Barack Obama is isolated in his desire for further spending - a plan he has been struggling to get through domestically.
US Treasury secretary Timothy Geithner told the BBC the world "cannot depend as much on the US as it did in the past".
Mr Geithner insisted the US and Europe would take "different paths, at a different pace" towards a common goal.
"It's going to require different things as we have different strengths and weaknesses," he said.
But the President cut an altogether different figure speaking just before travelling north to Canada.
"This weekend in Toronto, I hope we can build on this progress [in previous G20 meetings] by coordinating our efforts to promote economic growth, to pursue financial reform, and to strengthen the global economy," he said.
"We need to act in concert for a simple reason. This crisis proved, and events continue to affirm, that our national economies are inextricably linked.
"And just as economic turmoil in one place can quickly spread to another, safeguards in each of our nations can help protect all nations."
Mr Cameron is expected to meet Mr Obama tomorrow, the first time the two men have spoken in person since Mr Cameron entered Downing Street.
Before their one-on-one meeting, however, the two men will join Russia's Dmitri Medvedev and Chinese Premier Hu Jintao.