LONDON (Reuters) - Britain's shaky coalition government put on a show of unity on Monday, promising to stay together in what critics have dubbed a "marriage of inconvenience" to fix the country's ailing economy and tackle its big budget deficit.
Prime Minister David Cameron and his deputy, Nick Clegg, dismissed suggestions they were like a warring couple, in a rare joint public address following a week of acrimony that spurred talk of an imminent divorce.
"The coalition has come into question, some asking whether it has real momentum for the rest of this parliament, others even asking whether it should end," Cameron told reporters.
"I am even more committed to coalition government, to making this coalition government today than I was in May 2010 when Nick Clegg and I formed this government."
Cameron's Conservatives and Clegg's Liberal Democrats formed the coalition in 2010, promising to govern together until 2015, after a parliamentary election produced no outright winner.
But a major Conservative revolt last week forced Cameron to drop a vote on reforming parliament's unelected upper chamber, the House of Lords - a key Lib Dem demand.
Lib Dem lawmakers have so far reluctantly backed some of Cameron's proposals - including an unpopular hike in university fees - as part of the coalition deal, but the Conservatives' failure to keep their end of the bargain has put the frayed partnership under further strain.
Standing alongside Cameron, Clegg said the marriage between the two parties, cemented on a sunny post-election day at a rose garden news conference in 2010, was not on the rocks.
"It's tough to be in government in difficult times, it's not always a walk in the park, or in the rose garden," Clegg said. "None of that will stop us from continuing to govern in the national interest for the whole country."
Tackling a debt-laden economy in recession keeps them together for fear that voters would punish them for allowing squabbles over pet projects to split the government.
In their appearance, both men sought to look confident and at ease with each other, steering away from the thornier issues.
Focusing instead on the coalition's main mandate of fixing the economy, they also announced a $14.6 billion investment in railway projects.
But, away from their stage-managed show of unity, resentment among the Conservative and Lib Dem rank and file makes it difficult to see how the coalition can hold until 2015 parliamentary polls without major compromises.
Cameron suffered the biggest rebellion of his premiership last week when 91 fellow Conservatives defied him to veto the Lib Dems' plans for Lords reform, and it appears unlikely the freshly emboldened rebels will be more conciliatory in future.
The revolt forced a vote on Lords reform to be postponed until the autumn, when tensions are likely to flare again. Both parties are also at loggerheads over Britain's place in Europe, a dangerous issue that has helped fell previous governments.
"The credibility of the coalition is not enhanced if the tail is seen to be wagging the dog," senior Conservative lawmaker Bernard Jenkin said of his party's smaller coalition partners, the Lib Dems.
"If the Conservatives are seen as simply hostage to whatever the Liberal Democrats are demanding, it rather demonstrates the coalition's not a very strong arrangement," he said.
Menzies Campbell, a former Lib Dem leader, labelled the coalition a "marriage of inconvenience" and warned that party members could scupper Conservative proposals in retaliation for the Lords reform veto.
Some played down the spat, hoping voters will reward them in 2015 for overcoming their differences to nurse the economy after the deepest recession since World War Two.
"It has rocked the boat without doubt but I don't think it is threatening to sink the boat," Lib Dem Tom Brake said.
Conservative Karen Lumley, who rebelled against Cameron on Lords reform, said the row was "was a minor blip" and the coalition would carry on to "get the economy back on its feet".
Lords reform has little resonance among the British public, who are turning to the opposition Labour party according to recent opinion polls, putting the left-wing party ahead of both the Conservatives and the Lib Dems.
The Lib Dems in particular have haemorrhaged support since joining the Conservatives in government, and could be heavily punished in snap elections should they leave the coalition.
Additional reporting by Tim Castle and Matt Falloon; Editing by Maria Golovnina and Alison Williams