LONDON, England (AP) — Britain’s humbled Labour Party has begun a potentially bitter race for Gordon Brown’s successor following its ouster after 13 years in office — likely pitting brother against brother and possibly even husband against wife in a race riddled with intrigue and rivalries.

Ex-foreign secretary David Miliband, whose boyish charm left US Secretary of State Hillary Clinton swooning, leads the field to become the opposition leader who’ll take on Britain’s new coalition chiefs David Cameron and Nick Clegg — but his younger sibling Ed Miliband may emerge as his closest challenger.

While the contest may get fractious — the elder Miliband vowed it won’t spark a family feud.

“Family’s the most important thing in life,” he said yesterday, visiting a district in north London where Labour lost one seat. “Neither of us would do anything to compromise the family.”

For the first time since Tony Blair took Labour’s helm in 1994 the center-left group faces a scramble to secure its future — fearing the new governing alliance between its two political foes could banish Labour to the political wilderness for years.

It must also decide quickly on its ideological course: Stick with the market-friendly, centrist policies championed by Blair, or respond to the global financial crisis with a decisive lurch to its left-wing roots.

Labour, which won three consecutive election victories from 1997, lost 91 seats at the last election, and saw its brand tainted by the corrosive scandal last year over lawmakers’ expense claims. Three former members are facing criminal charges for false accounting.

The race to succeed Brown offers the party grass roots the first real decision over its leader since 1994. First, Brown sealed a secretive pact and agreed to stand aside in favor of Blair — then Brown was coronated unopposed when Blair quit as prime minister in 2007.

“We’re actually going to get an election for leader, for the first time in a very long time,” said Alex Hilton, a defeated Labour candidate at last week’s election.

Miliband, nicknamed “Brains” by Blair’s staff for his formidable intellect, is a tech-savvy policy wonk who won a strong reputation in Washington as he served as Britain’s foreign policy chief. At 44, he is drawn from the same generation as Cameron and Clegg, both aged 43, and seen by many as the most viable proposition to restore the Labour Party to prominence.

He already has one ringing endorsement from overseas — last year Clinton described Miliband to American Vogue as “so vibrant, vital, attractive, (and) smart.”

Blair could also pledge his support — though Miliband has attempted to open up some distance from his former boss, suggesting Britain would never have backed the 2003 US-invasion of Iraq if it knew weapons of mass destruction wouldn’t be found. Blair said recently that toppling Saddam justified the mission in any event.

But Miliband’s greatest challenger may be one of the men he knows better than any other — his 40-year old brother Ed Miliband.

The brothers, whose father Ralph was a respected Marxist theorist and mother Marion Kozak was a leftist academic, have similar political outlooks — though Ed is seen as closer to his party’s left-wing and was responsible for drafting Labour’s election manifesto.

As Britain’s former energy and climate change secretary, Ed Miliband took a lead role in negotiating at the December talks in Copenhagen aimed at reaching a global pact to reduce greenhouse gas emissions.

“They’re awfully close, from what I understand,” said James Cronin, a professor of British history at Boston College. A race between the two, he said, would be “fascinating.”