Ken Clarke contradicted David Cameron yesterday by suggesting that the idea of Britain having to go to the International Monetary Fund for emergency financial support was not “realistic”.

Mr Cameron, who appointed Mr Clarke as Shadow Business Secretary last week, said on Friday that Britain was running the risk of having to go to the fund. He warned that the money could run out.

However, asked on BBC One's Andrew Marr Show if he thought Britain could go bankrupt, Mr Clarke replied: “I don't think it is a realistic possibility although I am very gloomy myself, but it's not going to be calamitous.”

The difference of emphasis is a reminder of Mr Clarke's ability to embarrass colleagues in the leadership with his independent, outspoken style. Last week it was revealed that a few weeks before his appointment he had called his party's policy on Europe “silly”.

Vince Cable, the Liberal Democrat Shadow Chancellor, said: “Ken Clarke is absolutely right that this is a fundamentally different problem from the 1970s. His comments jarringly contrast with the rather shrill and hysterical comments from David Cameron and George Osborne. They have no memory of the 1970s, and have failed to see the uncomfortable parallels with the boom-and-bust cycles of the Conservative years, which Gordon Brown has now managed to duplicate.”

Geoffrey Robinson, a former Labour Paymaster General, said: “It's clear Ken Clarke is uneasy about David Cameron's shrill attempts to talk Britain down.”

Mr Clarke said that the Conservatives now had a settled policy on Europe which he described as “moderate” and he did not intend to try to change it. He said that he did not expect the case for Britain's entry into the euro to become an issue again in his “political lifetime”.

Mr Clarke added: “Of course, everyone knows that I don't agree with David and my colleagues on Europe entirely, and you can easily look at speeches where I've been at odds with them. But compared with recent years, I do think the settled policy of the party is moderate. I don't think anybody's going to change it and I'm not going to try to change it; I accept collective responsibility on the front bench and I accept that David is going to direct policy on eurosceptic lines.”

Mr Clarke said that, if the public found that he could not work with Mr Cameron and Mr Osborne because of “past disagreements over European issues that aren't actually topical at the moment”, they would think the party had “lost all sense of proportion”.

Gordon Brown will call today for greater international co-operation to stop countries using the financial crisis as a reason for retreating into their own markets.

After talking to President Obama, Mr Brown will this week meet the Prime Ministers of Korea, China and Japan, and the heads of international financial bodies, to press the case for co-operative action.

In his speech today Mr Brown will say that, just as it is important to avoid the protectionism of the 1930s, nations must also avoid a new form of financial mercantilism, retreating into domestic lending and financial markets.

He will say that the fragility of the global financial system must be addressed internationally. “If what happens to a bank in one country can - within minutes - bring potentially devastating effects on banks in a different continent, then only a truly international response - in policy and governance - can be effective. If we all co-ordinate our response, there will be a quicker global and, therefore, British recovery.”

He will add that the ability of banks in Britain to operate as the country wishes depends not only on their management at home but on getting regulation right internationally.

Times Recommends

• ‘Lame duck’ fear for FSA as chief quits
• Storm over bailout of EU's most ailing economy
• Northern Rock to drop 100% savings guarantee