LONDON - Prime Minister David Cameron is Britain's most popular major party leader and his Conservative Party the most trusted on the economy after helping revive it. But win or lose a knife-edge election this week, his career hangs by a thread.
If he loses, it's over instantly. And even if he wins but doesn't secure an overall majority, which opinion polls suggest no party will achieve, he could face a leadership challenge from inside his famously ruthless party before too long.
A descendant of King William IV, Cameron, who came to power in a coalition with the centre-left Liberal Democrats in 2010, says he wants to serve another five-year term "to finish the job" of fixing the economy. He also plans to deliver a European Union membership referendum, which he hopes will cure his country and party of its Eurosceptic angst.
But if he doesn't get the Conservatives re-elected on their own, with their first overall majority in the House of Commons for 23 years, he may struggle to serve out a full term.
"The Conservatives are very hard-nosed," Greig Baker, a former Conservative staffer who now runs a public affairs firm called Guide told Reuters. "If Cameron can deliver them ministerial red boxes he'll survive the election. But his long term prospects are very bleak. The party has never loved him."
Tim Bale, author of a history of the Conservative Party, says Cameron faces a rough ride from his party even if he keeps the keys to the prime minister's residence, 10 Downing Street. "If he manages to hang onto Number 10 I think they'll forgive him for a couple of weeks," said Bale. "Then it could be difficult."
While polls show voters generally like him personally, Cameron, 48, is the product of an unusually privileged background. The son of a wealthy stockbroker, he attended exclusive boys' boarding school Eton College and Oxford University, and married a woman who traces her ancestry back to another king - Charles II of England.
In a country acutely attuned to class, that rubs some Britons up the wrong way. One of his own outspoken lawmakers once called him and his finance minister "two posh boys who don't know the price of milk". Opposition lawmakers and parts of the media have likened him to "Flashman", a fictional upper class literary anti-hero of the nineteenth century.
His strongest boast is that he pulled the economy from a deep downturn to deliver one of the fastest growth rates in the developed world. But real wage growth has only just started to pick up, meaning many voters say the recovery hasn't benefited them.
Perhaps Cameron's biggest weakness is that he has failed to quash a perception among some voters that he heads "the nasty party," a term coined by one of his own ministers, Theresa May, more than a decade ago to urge the party to be more inclusive.
When Labour's Tony Blair beat them in three straight elections, Conservative insiders feared their failure was a result of a reputation for being indifferent to the poor, close to big business and intolerant of gays and ethnic minorities.
Cameron, who became Conservative leader in 2005, tried to change that. He started talking about the environment and a "Big Society" where communities would be given more power. In office, he legalised gay marriage, increased foreign aid and appointed Britain's first female Muslim cabinet member.