At the end of a fortnight in which international affairs have moved centre stage, David Cameron has clawed back ground from Labour, according to a Guardian/ICM poll. It shows Labour's poll lead has been squeezed to five points, after three straight months in which the gap in the polling series has been a solid eight points.

The political start to 2013 was dominated by debate in the buildup to the prime minister's scheduled speech on Britain's relations with Europe, which was postponed after the Algerian hostage crisis shifted attention towards terrorism and relations with the Muslim world.

Compared with the last Guardian/ICM survey, just before Christmas, Labour has slipped back two points to stand at 38%, while the Tories have inched up one to 33% and the Liberal Democrats have edged up two to 15%. The anti-European Ukip has slipped back one to 6%, after the record showing of 7% recorded by ICM in both November and December. The combined vote share of the other assorted minor parties now stands at 7%, down one over the month.

The five-point gap between the main parties is notably low not only by the recent standards of the Guardian/ICM series – which smooths some of the volatility seen in the raw data, using a formula that has been found to increase accuracy – but also compared with recent surveys by other organisations, which frequently give a more flattering picture of Labour's performance.

A separate YouGov poll for the Sunday Times at the weekend showed Cameron's personal standing as prime minister was starting to recover and also suggested that he had a solid lead over Labour's Ed Miliband and other political leaders as the man that voters would most trust to negotiate for Britain in Europe.

If the new focus on foreign policy is playing well for the prime minister, however, the Guardian/ICM survey reveals gathering doubts about a key plank of the government's strategy on the domestic front: the decoupling of benefits from inflation, which George Osborne announced in his autumn statement.

ICM asked voters to choose between two views of the chancellor's headline proposal for a 1% cap on benefit rises. Just 36% agreed with the coalition's argument that "squeezing benefits is fair, seeing as wages for workers are also being squeezed", whereas 58% inclined to the case made by the opposition that squeezing benefits and tax credits "is unfair, seeing as it will hurt the vulnerable, including many who people who do work hard for low pay".

No 10 has long been convinced that the "striving" majority of the public resents the "shirking" minority who rely on welfare, and will thus be concerned that by a substantial 22-point margin voters reject its argument in favour of this latest social security cut.

The long-running British Social Attitudes survey has indeed recorded a sharp drop in sympathy for people living on unemployment benefit over the last generation, although this evidence was collected before the coalition's cutting began in earnest.

Polls immediately before the autumn statement showed strong support for attaching stricter conditions to benefit payments – for example, YouGov found that by 73% to 17% people favoured mandatory unpaid work for the long-term unemployed – but surveys taken in the immediate aftermath of the chancellor's statement found less support for the specific cutbacks he proposed. Ipsos-Mori, for example, found that by 59% to 16% voters believed benefits should rise with inflation instead of by less than inflation, as Osborne proposed.

The detail of Monday's Guardian/ICM survey confirms a continuing gender gap, which will also concern No 10. The Conservatives are one point ahead of Labour among men, by 36% to 35%, but among women they languish 16 points behind, 29% to 45%.

The Conservatives will draw comfort from their strong showing among voters aged over 65, who are the most likely to turn out to the polls. Among this group, the Conservatives are ahead of Labour by 39% to 30%.

Among the minority parties, the Scottish Nationalists are at 3% and Plaid Cymru on 1%, both unchanged from last month. The Greens are down one, on 2%, and the British National party is unchanged on 1%.

ICM Research interviewed a random sample of 1,001 adults aged 18+ on 18-20 January 2013. 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.