London - The man of the hour in Britain's hottest prime minister's race in decades is tall and baby-faced, a self-proclaimed atheist who wants the nation to end its "slavish" devotion to Washington and consider trading in the revered British pound for the euro. Almost overnight, he has injected an ingredient into the race that has the British establishment quaking: the Clegg Factor.

That man is Nicholas Clegg.

In a country with a legacy of two dominant parties - Labor and the Conservatives - Clegg's stunning surge since Britain's first-ever televised prime minister debates last week has given his typically third-place Liberal Democrats the lead in at least two major polls. Only two weeks ahead of the May 6 elections, Clegg's rise is upending a nation known for the traditional political machines of Margaret Thatcher and Tony Blair. His against-the-odds message of change is energizing young voters and has the British press comparing him to President Obama.

For the first time, analysts are openly entertaining the prospect of a Clegg victory, or at least an outcome so close that it leads to Britain's first hung Parliament since the 1970s. Investors are so worried about a fragile, paralyzed government emerging in deeply indebted Britain that the pound fell on global markets last week after Clegg won the debates.

Clegg has argued that Britain's "special relationship" with the United States is outmoded, that Britain can no longer afford to be the world's No. 2 policeman. He has called for the nation to consider reducing its nuclear deterrent and warned against "saber-rattling" on Iran.

"If you're the U.S. administration, you might be a bit worried at the moment because you haven't had enough lunches with the Liberal Democrats, and you might want to be inviting Nick Clegg over to the embassy for dinner right about now," said John Curtice, a professor of politics at the University of Strathclyde. "You also might be a bit worried about whether he will continue to follow the American line."

In a speech Tuesday, Clegg bluntly called Britain's "linchpin" relationship with the United States a Cold War relic and said the invasion of Iraq was "illegal." He praised Obama, and his more internationalist stance, but maintained that both nations should rethink their priorities.

"I think it's sometimes rather embarrassing the way Conservative and Labor politicians talk in this kind of slavish way about the special relationship," Clegg said. "If you speak to hard-nosed folk in Washington, they think it's a good relationship but it's not the special relationship." He later added, "They are moving on, why on earth don't we?"

Clegg, 43, owes his surging poll figures to the U.S.-style, prime-time debates introduced this year. When he took the stage last week in Manchester, Clegg was running a distant third. Sounding alternately folksy and astute, he stole the spotlight from Prime Minister Gordon Brown, the Labor incumbent, and David Cameron, the Conservative candidate who had been the longtime front-runner.

But with Brown slipping, and Cameron locked in a fierce battle with Clegg, all eyes will be on Clegg's performance at the second debate, on foreign policy, set for Thursday night.

Because of the nature of the British electoral process, Clegg's party could win a majority of votes but still not win enough seats in Parliament to earn the right to form a government. He would need roughly 40 percent of the vote to bring his "Lib Dems" to power, with polls showing them now at 30 to 34 percent. That compares with around 20 percent before the debates.

If Clegg falls short, Cameron or Brown could be forced to form a coalition government with the Liberal Democrats or one of several smaller, regional parties. The last time that happened in Britain - in 1974 - the government fell within eight months. Even more likely is the emergence of a weak minority government that could paralyze attempts to slash the massive budget gap here, triggering fears of a debt crisis.

Born to a Dutch mother and a father descended from Russian nobility, Clegg is not your average Englishman. The multilingual career politician was educated at Cambridge and the University of Minnesota. He and his Spanish wife have three sons - Antonio, Alberto and Miguel. In an Anglican country, they raise their children as Roman Catholics - though Clegg publicly professed to be an atheist in 2007.

Clegg has also tapped voter rage over the economy and a political class embarrassed by an expenses scandal last year that showed that some lawmakers had taxpayers paying for duck pools and nannies.

But analysts say he is vulnerable on several fronts. Cameron in particular is coming down hard on Clegg in speeches for his liberal stance on immigration and his vision of a Britain more closely linked with the European Union - positions seen as out of step with the public.

But for many, it is Clegg's style - not policies - that is giving him the edge over Brown and Cameron.

"You can't imagine having them around for dinner, can you?" said Patrick Lynch, 41, an architect in the key London battleground of Islington. "Brown looks like your grandfather and Cameron was born middle-aged." But Clegg, he said, "is a modern human being."

- - -

Special correspondent Karla Adam contributed to this report.