LONDON, (AP) – Britain woke up to a new political era Wednesday with the first coalition government since World War II — an unlikely marriage between the Conservative Party of right-wing icon Margaret Thatcher and the left-leaning Liberal Democrats.

Details of the coalition alliance are trickling out with the Liberal Democrats having already won several Cabinet seats. It will be one of the least experienced governments since Tony Blair’s Labour Party won its landslide victory in 1997.

With a handshake, smiles and waves, the Conservative Prime Minister David Cameron welcomed his new coalition partner, Deputy Prime Minister Nick Clegg, outside the shiny black door at 10 Downing Street and set off on the business of running the country. Cameras flashed.

The alliance was necessary because no party won a majority of parliamentary seats. Voters struggling to make ends meet during the recession were enraged after a damaging expense scandal last year tarred lawmakers from all three parties with claims on everything from pornography to chandeliers.

The government will immediately begin tackling Britain’s record 153 billion-pound ($236 billion) deficit. It is still unclear whether the Liberal Democrats will back the Conservatives’ plan to begin immediate spending cuts — a punishing course of action that isn’t likely to win praise from the electorate.

One of the first calls of congratulation to the new prime minister came from President Barack Obama, an acknowledgment of Britain’s most important bilateral relationship. Obama invited Cameron to visit Washington this summer.

Both Cameron and Clegg have acknowledged that Labour under Blair was too closely tied to Washington’s interests. Both men back the Afghanistan mission, but Cameron hopes to withdraw British troops within five years. Clegg has said he’s uneasy at a rising death toll. Leaner coffers may also mean less money to enter foreign-led military operations.

Relations with European neighbors could also become problematic. Cameron’s party is deeply skeptical over cooperation in Europe and has withdrawn from an alliance with the parties of Germany’s Angela Merkel and France’s Nicolas Sarkozy. Clegg, once a member of the European parliament, has long been pro-European.

Once described as sandal-wearing hippie academics, Clegg’s Lib Dems emerge from the political fringe to the top rung of government. Among the most visible will be Vince Cable, who will take an as yet unspecified post in charge of Britain’s banks, the BBC reported.

Labour, meanwhile, took steps to regroup, with the maneuvering under way for the job of party leader. David Miliband, the former foreign secretary, has emerged as a top candidate and has earned the backing of another early favorite, former Home Secretary Alan Johnson.

Brown’s deputy Harriet Harman would become interim Labour leader until a formal leadership takes place to select his permanent successor.

The 43-year-old Cameron became Britain’s youngest prime minister in almost 200 years — the last was Lord Liverpool at 42 — after cementing a coalition deal with the third-place Liberal Democrats. Clegg and four other Liberal Democrats received Cabinet posts. A number of other Liberal Democrats would receive junior posts.

The agreement, reached over five sometimes tense days of negotiation, delivered Britain’s first coalition government since World War II.

“This is a genuine compromise between the parties,” said William Hague, the new foreign secretary. “There are many things the Liberal Democrats have had to swallow that are very difficult for them, just as there are some things — like holding a referendum on a new voting system — that are very difficult for the Conservative Party to accept. That means, of course, there will be people in both parties who quietly wish it hadn’t happened, I’m sure.”

Cameron and Clegg agreed to a pact after the Conservative Party won the most seats in Britain’s May 6 national election, but fell short of winning a majority of seats in Parliament.

Cameron’s Conservatives said senior lawmaker George Osborne will serve as Treasury chief, and lawmaker Liam Fox as defense secretary.

Other leading positions were being finalized, as were key policy decisions ahead of the presentation of the coalition’s first legislative program on May 25.

The coalition has already agreed on a five-year, fixed-term Parliament — the first time Britain has had the date of its next election decided in advance. Both sides have made compromise, and Cameron has promised Clegg a referendum on his key issue: reform of Britain’s electoral system aimed at creating a more proportional system.

“Nick Clegg and I are both political leaders who want to put aside party differences and work hard for the common good and for the national interest,” Cameron said Tuesday.

Brown’s resignation ends five days of uncertainty after last week’s general election left the country with no clear winner. It left Britain with its first so-called hung Parliament since 1974. Britain’s Conservatives won the most seats but fell short of a majority, forcing them to bid against the Labour Party for the loyalty of the Lib Dems.