The Foreign Secretary, David Miliband, has backed Tony Blair to become the first president of the European Union, arguing that his leadership would enable Europe to compete with China and the United States on the world stage.
Miliband said that the new EU president needed to be someone who was guaranteed the highest access to world leaders.
"I think it would be very good for Britain as well as very good for Europe if Tony Blair became a candidate," he told the BBC.
Blair, who has also been endorsed by the Italian prime minister Silvio Berlusconi, has not publicly declared his interest in the position. It is thought that other likely candidates for the post include the Dutch prime minister, Jan Peter Balkenende and Jean-Claude Juncker, the prime minister of Luxembourg.
Miliband also ruled himself out of the running to become Europe's foreign affairs chief, the second post created by the Lisbon Treaty.
"I'm not a candidate for that, I'm not available, I've got a job that I'm absolutely committed to and I'm proud to do," he said.
He said that the Lisbon Treaty would help ensure Europe remained relevant in a multipolar world.
"It needs to take that opportunity, otherwise we will find the world run by America and China without any reference to us," he said. "It all comes down to what the heads of government want the job to be. It's about whether or not Europe wants a strong leader in that position. I think that hasn't yet been resolved in the minds of a number of Europe's leaders."
He added that other European countries were bemused by the Conservatives' opposition to the former prime minister standing for the position.
"In every other country they would be delighted if one of their former prime ministers was being nominated by governments around Europe," he said.
But the Conservative shadow Europe minister, Mark Francois, said: "The British people do not like the Lisbon treaty and if it was used to impose Tony Blair as European president without the British people having a say it would only underline the treaty's complete lack of democratic legitimacy."
EU leaders will meet in Brussels on Thursday to agree the remit of the new president and will privately begin discussing possible candidates.
