Published: May 12, 2010 5:02 PM EDT

 LONDON  - Former rivals David Cameron and Nick Clegg hailed their new coalition government as the coming of a new era in British politics on Wednesday, glossing over policy differences but pledging to tackle the country's most pressing problem - the looming deficit.

The Conservative and Liberal Democrat leaders stood in Downing Street's sun-dappled garden and promised that their partnership was united by common purpose and will survive for a full five-year term. They pledged sweeping reform to Parliament, civil liberties laws and on ties to Europe.

With handshakes, wide smiles and a sprinkling of jokes, Clegg and Cameron showcased their extraordinary pact, which ousted ex-leader Gordon Brown, whose Labour Party held power for 13 years.

The one-time foes banded together after Britain's election last week denied all parties a majority - leaving the country with its first hung Parliament since 1974. Britons struggling to make ends meet during a punishing recession gave no single group a mandate, and many were left enraged at politicians of all stripes after a damaging lawmakers' expense scandal last year.

"Until today, we have been rivals: now we are colleagues," said Clegg - the surprise upstart of Britain's election campaign, who won a newly enhanced profile but saw his party lose seats in the vote. Side by side, Clegg turned to his new partner and spelled out their joint message. "This is what the new politics looks like," he said.

Cameron has appointed their joint Cabinet - including four other members of Clegg's Liberal Democrat party - and the men laid out a draft program for the next five years. They pledged to keep Britain out of the euro currency until 2015 at least; agreed immediate 6 billion pounds (US$9 billion) cuts to government waste and vowed House of Lords members would be elected, rather than appointed.

Cameron said the government will immediately begin tackling Britain's record 153 billion-pound ($236 billion) deficit - and convene a first meeting Wednesday of a newly created a National Security Council, focused on the Afghanistan war. Both look deeply relaxed in each other's company. Reminded he had once been asked "What's your favorite joke" and answered "Nick Clegg," Cameron responded with an exaggerated grimace while Clegg asked, "did you really say that?" - and pretended to walk away from the podium. "Come back," Cameron implored, adopting a comic tone, predicting former rivals on both sides will "have things that we said thrown back at us."

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's government under ex-leader Tony 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. The new foreign secretary, William Hague, told the BBC that the new government wanted a "solid but not slavish relationship" with the United States and described the so-called special relationship between the two countries as being of "huge importance."

"No doubt we will not agree on everything," Hague said of the United States. "But they remain, in intelligence matters, in nuclear matters, in international diplomacy, in what we are doing in Afghanistan, the indispensable partner of this country." Hague is expected to speak by telephone later to U.S. Secretary of State Hillary Clinton, and soon travel to the United States and Afghanistan.

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. Their coalition agreement includes a tough stance over Europe, pledging to oppose the transfer of any additional sovereign power to Brussels.

Cameron extended his first invitation for formal talks to Sarkozy, who will visit London on June 18. The date is highly symbolic for France as it is the day that Charles de Gaulle launched his appeal from London via the BBC for the French to resist the Germans during World War II.

The new British leader also spoke Wednesday with two key allies, Chinese Premier Wen Jiabao and Indian Prime Minister Manmohan Singh. The new British chief has vowed to build a "new special relationship" with India, believing the country can become a major political and trade partner.

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 becomes 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. Cameron named 38-year-old Conservative lawmaker George Osborne as Treasury chief, the youngest chancellor for more than a century - and, critics say, one of the most inexperienced. Liberal Democrat negotiator David Laws was appointed as chief secretary to the Treasury - a highly respected role as deputy to Osborne.

Vince Cable, the highly popular Liberal Democrat deputy leader, becomes business secretary. Lawmaker Liam Fox will serve as defense secretary, Kenneth Clarke as justice secretary and Theresa May as Home Office 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.

Both sides made compromise to strike their deal. Cameron promised Clegg a referendum on his key issue: reform of Britain's electoral system aimed at creating a more proportional system. In turn, Clegg ditched opposition to a 20 billion pound ($32 billion) program to replacing the country's fleet of nuclear-armed submarines.