Tories' strong week leaves Cameron close to a majority

The Conservative lead over Labour widened yet further in the week that the date of the general election was finally announced. As a result, the party now appears tantalisingly close to an overall majority, but is still somewhat short of what it needs to be confident of outright victory on 6 May.

Our latest poll of polls, based on no less than 13 national polls conducted during the course of last week, now puts the Conservatives on 39 per cent, up one point on the previous week. That means David Cameron's party is now nine points ahead of Labour, whose average vote, at 30 per c ent, is unchanged.

It is the Liberal Democrats who have edged back a little – a one point increase in their vote immediately before Easter has not been sustained.

Overall, since the Budget, the Conservative lead has widened by no less than three points. Labour's prospects of coming first in seats, courtesy of the biased workings of the electoral system, have receded significantly.

However, the electoral system might yet still deny the Conservatives an overall majority. Even with the Liberal Democrats back down to 19 per cent, the Tory lead is, on the conventional arithmetic, just insufficient to deliver the party 326 seats. At 318 seats, the current projection in effect means that the Tories' chances of securing a majority are still a little short of evens.

There is, of course, no guarantee that the conventional arithmetic will be correct. It assumes the ups and downs in party fortunes will occur evenly across the country. The Tories' hopes of outright victory depend in part on the expectation, previously supported by a number of polls, that they will achieve an above-average swing in the vital key marginals they have to win from Labour.

However, two new polls conducted wholly or mostly during the last week in some of the key Labour/Conservative marginals suggest the Tory advance in these seats too may be currently a little below what the party is likely to need for outright victory.

MORI put the swing from Labour to the Conservatives since 2005 in these seats at 5.5 per cent, ICM a little higher at 6 per cent. However, even with the Liberal Democrats down on 19 per cent, the Tory target is, at 6.5 per cent, a little higher still. Even that will only be sufficient if the party also makes gains in Liberal Democrat/Conservative marginals – in which so far no specific polling has been conducted.

Doubtless the Tory advance over the past fortnight will convince the party it has made the right call on national insurance and will now be able to drive home its advantage with its announcement over the weekend of a tax break for some married couples.

But this latest announcement might prove more vulnerable to attack. Two polls published yesterday suggested a majority of the public do not necessarily agree that married people should be treated more favourably than those who are unmarried, let alone those who are widowed or divorced. It remains to be seen whether Labour and the Liberal Democrats can successfully exploit this potential line of attack. However, what matters for most voters are not the details of policy but their overall impressions of the parties. Labour's real difficulty is that some of the broad impressions the public have formed of it are potentially toxic.

Voters are still not convinced that Labour can run the economy more effectively than the Conservatives. At the same time they more readily associate Labour with both higher taxes and more wasteful spending. And the last thing voters are likely to support is higher taxes for government to waste.

John Curtice is Professor of Politics, Strathclyde University