Conservative support drops to 28% after autumn statement, the party’s lowest score since May last year

Conservative support in Britain has fallen in the aftermath of the chancellor’s autumn statement, which pencilled in deep public expenditure cuts for years ahead, according to the latest Guardian/ICM poll.

The Tories dip three points on November to 28%, while Labour inches up one to 33%, giving Ed Miliband a five-point lead. The Liberal Democrats climb three from last month to 14%, while Ukip stands still on 14%, for the third month in a row. The Green party are on 5%.

The Conservative score takes the party below 30%, which ICM’s Martin Boon describes as the likely “defeat threshold” for next year. It is the party’s lowest score in the series since May last year.

At that time, the economic recovery was less well-established and Labour was generally running clearly ahead. In the months since, the race has tightened, but the latest survey suggests George Osborne’s Commons set-piece may have contributed to a Tory reverse.

On the day of the autumn statement, reforms to stamp duty initially dominated the headlines, but as the dust settled attention turned to the Office for Budget Responsibility’s remarks about the plans implying the state being rolled back to its smallest share in the economy since the 1930s.

Pressed on whether “the chancellor is taking the tough decisions that Britain needed to live within its means”, only 35% of voters agreed, whereas 55% were instead inclined to say that Osborne was “going too far, and imposing cuts that will endanger important public services”.

Nor were such concerns restricted to left-leaning voters. A clear majority of Ukip supporters, 57%, charged the chancellor with going too far, as did almost a third (31%) of those who had backed the Conservatives in 2010.

ICM also asked voters how they thought Britain should set about repaying its debts. Past governments, including Sir John Major’s Conservative administration in the 1990s, have closed fiscal deficits through a mix of tax rises and spending reductions, but in his party conference speech David Cameron insisted he was “confident we will find the savings we need through spending cuts alone”.

An overwhelming majority of voters turn out to prefer a more balanced approach to deficit reduction, with only 16% believing that pure expenditure cuts, with no tax rises, is the best way to go.

A similar 15% would like to see tax rises do one-third of the work in filling the Treasury’s black hole, while 13% would like to see taxes contribute two-thirds.

Another 14% would prefer to avoid all spending cuts by relying entirely on higher taxes. By some margin, though, the most preferred option is a half-and-half mix of spending restraint and higher taxes – the preferred option of 34%.

“Very few voters will have studied the autumn statement’s small print,” says Boon, “but today’s survey suggests that the tough decisions that flow from George Osborne’s decision to aim for a surplus in the next parliament could be tougher than the public are prepared to stomach.”

• ICM Unlimited interviewed a random sample of 1,001 adults aged 18+ by telephone on 12-16 December 2014. Interviews were conducted across the country and the results have been weighted to the profile of all adults. ICM is a member of the British Polling Council and abides by its rules.