The apathy party has been biggest loser so far

Labour's poll wobble appears to have steadied. Whereas four polls published on Tuesday, just as the Prime Minister was about to set off for the Palace, put Labour's lead, on average, at just 1 point, the latest polls, including three published yesterday, on average, put the Government four points ahead.

Labour's poll wobble appears to have steadied. Whereas four polls published on Tuesday, just as the Prime Minister was about to set off for the Palace, put Labour's lead, on average, at just 1 point, the latest polls, including three published yesterday, on average, put the Government four points ahead.

All is not as it seems, however. Much of the apparent restoration of Labour's poll lead is the result of one poll. Last Tuesday MORI claimed the Conservatives had a five-point lead, the only poll published that day to put Michael Howard ahead. Now it puts Labour as much as seven points ahead, the biggest lead any poll has given Labour since Easter.

Other polls have shown far less movement. ICM's latest poll puts the Labour lead at four points, up just one on last Tuesday. YouGov, meanwhile, estimates Labour's lead to be only two points, again up just one point on its previous poll last Friday. Both still put Labour's lead at less than they did on at least one occasion during March.

What accounts for MORI's extraordinary movement? Unlike any other pollster, MORI's headline figures are based on just those who say they are certain to vote. In its poll, published last week, MORI found that, while 74 per cent of Tory supporters said they were certain to vote, only 57 per cent of Labour voters were similarly inclined, a rather bigger gap than found by most other recent polls. As a result, what was a five-point Labour lead amongst all voters became a five-point Conservative lead among those certain to vote.

But it appears that, now the election gun has been fired, voters are beginning to take an interest, suggesting fears that there would be another record low turnout on 5 May may be premature. As many as 61 per cent now say they are certain to vote, up six points on last week. And it appears that the relative reluctance of Labour voters in particular to go to the polls has diminished. As a result, what was an 11-point Labour lead among all voters in the latest MORI poll fell to just seven points among those certain to vote.

Still, even if Labour's recovery has not been quite so spectacular as it might seem at first glance, there are undoubtedly two good pieces of news for the party in the latest polls.

First, at worse, it does still hold a narrow lead in votes, a lead that given the advantage it derives from the electoral system could be sufficient to secure Mr Blair a third term. Second, the party's attempts to persuade its supporters that, whatever their doubts they need to go to the polls in order to ensure Mr Howard does not win, may be beginning to have their desired effect.

Labour might be particularly relieved it has apparently not suffered from the threatened closure of the Rover plant at Longbridge, a story which broke during the middle of the period when the latest polls were being conducted.

There is a hint in the latest ICM poll that the news has had some impact on voters - the proportion saying the economy would be important in deciding how they vote is up three points on last week. But there is no evidence at all that people's confidence in Labour's ability to run the economy has been undermined. At 45 per cent, the proportion saying Labour has the best policies on the economy is actually up two points.

Election day is, however, still a long way off and Labour's support fell by five points in the last two campaigns. It still cannot afford any such repetition.

John Curtice is professor of politics at Strathclyde University