Support for the Liberal Democrats has slumped back to approach its lowest level since the row that surrounded the party's formation, from which it didn't recover until 1991, according to The Independent's "poll of polls".
Nick Clegg is now the most unpopular third party leader since David Owen led the Social Democratic Party (SDP) in 1989. The Liberal Democrats' 11 per cent rating in the first poll of polls since last May's election highlights the dramatic slide in their fortunes since they entered the Coalition with the Conservatives. The average polling figures for the Liberal Democrats were at their lowest in 1990 at a rate of 9.3%.
The 57 Liberal Democrat MPs would be reduced to a rump of just 15 at the next election if this level of support were to be repeated then.
Labour is now on 40 per cent and the Tories on 38 per cent, giving Labour an overall majority of 14, according to the weighted average of the regular surveys by ComRes, ICM, Ipsos MORI and YouGov.
John Curtice, professor of politics at Strathclyde University, who compiled the figures, said that the costs and benefits of the Coalition had been distributed very unevenly between the two parties in it.
"It is clear that the tone and direction of the Coalition Government has upset many people who voted Liberal Democrat in May, and before, while for the most part those who voted Conservative have been reasonably content with what has transpired," he said.
"Liberal Democrat support is now lower than at any time since the party's troubled years following the merger of the Liberals and SDP." Mr Clegg's party is as unpopular as when the third party propped up an ailing Labour government in a Lib-Lab pact before the 1978-79 "winter of discontent".
The parallel is not an encouraging one for Mr Clegg, since its number of MPs fell to 11 at the 1979 general election – its worst result at any election between February 1974 and 2010.
"It seems that history is repeating itself so far as public reaction towards the party's involvement in support for a government engaged in cutting public expenditure is concerned," said Professor Curtice. "It certainly should not be presumed that demonstrating an ability to take tough decisions in the national interest will eventually reap a reward in the ballot box."
Charting the Liberal Democrats' decline last year, the "poll of polls" shows that the party began to lose support for entering the Coalition but hit real trouble after the emergency Budget in June, which was followed by a three-point drop in its ratings.
An autumn dominated by the row over university tuition fees, on which the Liberal Democrats made a spectacular U-turn, led to a further five-point fall.
"Mr Clegg has clearly taken a serious hit personally," said Professor Curtice. Only 38 per cent of people are satisfied with his performance as Deputy Prime Minister, while 50 per cent are dissatisfied. These are the worst ratings for a third party leader since Dr Owen's score in December 1989, when 24 per cent were happy with him and 52 per cent unhappy.
Although the Liberal Democrats' decline is the most striking feature of the "poll of polls," it also contains bad news for the two other main parties.
The Conservatives will be worried by the speed at which the Coalition has seen its popularity decline. It is now close to being as unpopular as Margaret Thatcher's government at the same stage after she won power in 1979. In contrast, Tony Blair's government retained a positive net rating in December 1997.
However, David Cameron is doing better personally than Baroness Thatcher was at this stage of the political cycle. Forty-eight per cent of people are satisfied with him and 44 per cent dissatisfied. Lady Thatcher's ratings were 41 and 49 per cent respectively, while 61 per cent were happy with Mr Blair and only 27 per cent unhappy.
Professor Curtice said: "Although the Tories have not suffered a direct electoral reverse, the collapse in the Lib Dems' vote to Labour's advantage has harmed the Conservative Party's ability to win a general election in the immediate future. The Tories thus have their own good reason to want the Coalition to stay together."
Labour is doing better than the Tories were after Mr Blair's 1997 landslide but should not be celebrating yet. At the same stage after Lady Thatcher's 1979 election win, Labour was four or five points ahead in the polls but still went on to lose the next three elections.
Ed Miliband's personal ratings are also a cause for some Labour concern. Professor Curtice said that he had had an unusually strong impact – with no previous Leader of the Opposition having more people giving either a positive or negative view of him three months into his leadership, rather than saying "don't know".
Mr Miliband has "suffered an unusually negative reaction", Professor Curtice said. While 35 per cent of people are satisfied with Mr Miliband's performance, 34 per cent are dissatisfied, giving him a "net satisfaction rating" of plus 1 per cent. Only Michael Foot had more people dissatisfied with his leadership at this stage, while only Mr Foot and William Hague had a worse overall rating. Even Iain Duncan Smith, who was ousted before fighting a general election, had a "net satisfaction rating" of 2 per cent at this point.