Tory poll lead falls to four points

New ICM poll suggests Labour could remain the single largest party after the election.

Labour could yet emerge as the single largest party after the next election, according to a new opinion poll which shows the Conservatives' lead falling to just four points.

A day before Gordon Brown is expected to call a general election, the latest ICM survey for the Guardian put the Tories down one point to 37 per cent - the party's lowest support in an ICM poll since February 2008 - with Labour up four to 33 per cent and the Liberal Democrats down two to 21 per cent. If repeated at the election on a uniform swing, the latest figures would leave Brown 30 seats short of an overall majority in a hung parliament.

The poll will dampen Tory hopes that the party had regained a comfortable lead over Labour after promising to reverse part of the government's planned rise in National Insurance. A recent Sunday Times/You Gov poll put the Conservatives ten points ahead of Labour, a lead which, so long as the Tories perform well in the marginals, should be enough to give David Cameron a small majority.

But there was better news for the Conservatives in a new Opinium poll for the Daily Express. The survey put the Tories up to 39 per cent, ten points ahead of Labour, who were also up one to 29 per cent.