David Cameron will today press Germany for speedy action to deal with the crisis in the eurozone as he flies to Berlin for talks with chancellor Angela Merkel.
Ms Merkel is coming under growing pressure to put German taxpayers' money behind measures such as "eurobonds" which would spread the burden of debt from ailing economies like Greece among the 17 single currency members.
Mr Cameron is expected to tell her that he and US president Barack Obama are agreed that an "immediate plan" is needed to save the eurozone. Last night he warned that "speed is of the essence" if jobs, opportunities and growth are not to be lost.
"Clearly the euro zone crisis is the biggest threat to the world economy today," he told journalists.
However, he will also be wary of being seen to lecture euro members from a position outside the single currency.
He has cautioned against holding Germany solely responsible for delays in dealing with the long-running debt crisis.
"I don't think it's right to try to lay all the responsibility on one person. It is everyone in the eurozone and throughout the EU," said Mr Cameron, during a visit to Norway last night. "We all need to do the right things to help ease this crisis."
With the re-run Greek election on June 17 followed by crucial summits of the G20 in Mexico and the European Council in Brussels, pressure is on for concrete action by the end of this month.
Mr Cameron has been calling for some months for "decisive" action from eurozone members to stand behind their currency and he will be bolstered in today's talks by the outcome of Tuesday's phone call with Mr Obama.
Downing Street said that the Prime Minister and US president "agreed on the need for an immediate plan to tackle the crisis and to restore market confidence, as well as a longer-term strategy to secure a strong single currency".
In a key speech in Manchester last month, Mr Cameron threw his weight behind the eurobond proposal, saying: "The eurozone needs to put in place governance arrangements that create confidence for the future.
"And as the British Government has been arguing for a year now, that means following the logic of monetary union towards solutions that deliver greater forms of collective support and collective responsibility, of which eurobonds are one possible example.
"Steps such as these are needed to put an end to speculation about the future of the euro."
But Ms Merkel has indicated that it would be wrong to establish eurobonds unless they are accompanied with closer fiscal union between eurozone states.
She said at the weekend: "You can't demand eurobonds but not be prepared for the next step in European integration. We won't be able to create a successful currency like that and no-one outside will lend us money any more."
Mr Cameron was travelling from Oslo to Berlin today with his Norwegian counterpart Jens Stoltenberg.
They will join Ms Merkel at a "town hall meeting" where they will answer questions from German, British and Norwegian students before Mr Cameron and the German chancellor hold bilateral talks.
No breakthroughs are expected in today's talks, which are being seen as paving the way for progress once the Greek elections are out of the way.
But speaking in Oslo last night, Mr Cameron said: "Speed is of the essence. Every day that the European economies are stagnant are days when opportunities are lost, wealth is lost, jobs can be lost.
"So, we need to get our economies moving.
"Clearly the eurozone crisis is the biggest threat to the world economy today. It is the biggest challenge that we all face. It is the thing we have to fix, to sort out, to help restore growth right across the world economy."
He reiterated his call for eurozone states to build an effective "firewall" to prevent contagion spreading beyond Greece; to ensure banks are well capitalised; to create a system of fiscal burden-sharing; and to enact a supportive monetary policy across the single currency area.
The talks in Berlin take place against the backdrop of uncertainty in Spain, whose economy minister has been forced to deny that his country is about to seek a bailout of its banks.
Mr Cameron declined to comment on Spain's complaint that the credit markets are "effectively shut" to the country because of the high yields demanded by international lenders.
"I don't want to speculate on any individual country," he said. "I have said throughout that proper bank recapitalisation is important for all European countries. That is a vital part of the stability part of the package I have been talking about."