Just 16% of voters think the Conservatives and Liberal Democrat will remain in government together until 2015, according to a poll out today.
The public had already been sceptical about the ability of the coalition to survive for a full five years in the Guardian/ICM's poll in May, when only 33% expected it would cling on until May 2015.
Its latest survey has found that number dropping to just one in six, suggesting a dramatic drop in confidence in David Cameron and Nick Clegg's ability to keep working together in recent weeks.
The divisive failure of the government's Lords reform agenda is thought to have driven falling public confidence in the staying power of the government.
Tory ministers were unable to stave off a rebellion from their backbenches over Lib Dem-supported plans to create an 80% elected upper House.
Clegg responded last week by abandoning the reforms for good - and lashed out at the Tories for breaking their commitments. The Lib Dem leader withdrew his party's support for planned boundary changes as a result.
Fifty-four per cent of voters now expect the government will not last into 2015, according to today's poll.
Although the coalition parties legislated to secure fixed-term parliaments of five years - a precondition of entering into government together - there are two ways in which a general election could take place before 2015.
A motion of no confidence passed by the Commons would trigger an opportunity for the formation of a new government. If the new government cannot secure a majority in the Commons within 14 days an election is triggered.
A more likely scenario might be a more straightforward motion in the Commons for an early general election which secures a two-thirds majority in favour.
Many Tory backbenchers have contemplated a third possibility, in which the Lib Dems drop down to a 'confidence and supply' arrangement in which they allow the Conservatives to remain in power as a minority government for the 12 months before May 2015.