Observer/Opinium poll puts Labour on 36%, with the Tories on 29% and Ukip down three points to 16%

Labour has opened up a seven-point lead over the Conservatives in the latest Opinium/Observer poll, which also shows a sharp fall in the personal approval ratings for the Ukip leader, Nigel Farage.

The survey will be a boost for Labour and its leader, Ed Miliband, who has endured a torrid time since the autumn conference season as the political parties prepare to enter a general election year.

It is the second poll in a week showing that the Tories have lost ground since chancellor George Osborne’s autumn statement earlier this month, in which he spelled out the need for several more years of deep cuts to public spending.

The survey will be worrying for Farage, as it shows his personal ratings diving to a level below those of Cameron. Photograph: Guim

The poll by Opinium puts Labour up two percentage points on a fortnight ago on 36%, while the Conservatives are unchanged on 29%. Ukip has fallen by three points to 16%, while the Liberal Democrats are also unchanged on 6%, just one point ahead of the Greens, who are on 5%.

If replicated at the general election, the figures could see Labour secure a majority in the Commons of more than 80 seats. Last week an ICM poll for the Guardian also showed Labour stretching its lead, to five points.

Since Miliband’s party conference speech in Manchester in September, after which he was mocked for forgetting to mention the deficit, Labour and the Tories have been neck and neck in a majority of polls, with Labour’s lead being wafer-thin.

The poll puts Labour up two percentage points on a fortnight ago on 36% Photograph: Guim

The Opinium survey will also be worrying for Farage, as it shows his personal ratings diving to a level below those of David Cameron, following a series of controversies, including his public comments about the need for women to be discreet when breastfeeding. Farage’s rating has dropped to -17% (the percentage of voters who approve of his performance minus those who disapprove), a fall of eight points since a fortnight ago and the lowest score recorded for him by Opinium.

Although Cameron still scores best on this measure by some margin, Miliband has narrowed the gap. Cameron’s rating fell by two points to -11%, while Miliband’s improved by three points to -28%. Nick Clegg was on -48%.

Douglas Alexander, chair of Labour’s general election strategy, claimed that the Tories were alienating voters as they were intent on paring back public services. “In the final weeks of this year, the Tories have made a major error by exposing themselves as a party intent on slashing back public services to levels not seen since the 1930s, when we didn’t have the NHS. Theirs is a project motivated by ideology, not necessity,” he said.• Opinium Research carried out an online survey of 1,957 GB adults aged 18+ between 16 and 19 December 2014. Results have been weighted to nationally representative criteria.