John Curtice: Lib Dems enjoy a last-minute bounce, but their vote remains 'soft'

Over the past week, Labour has been desperately warning voters of the dangers of flirting with the Liberal Democrats. Yet, far from registering a drop in Liberal Democrat support, our exclusive NOP poll puts Charles Kennedy at a higher level than at any time since we began regularly taking the nation's political pulse last autumn. After flatlining for the whole of the campaign, it appears that the Liberal Democrats are now enjoying a last- minute campaign bounce.

These figures may well make Labour strategists wonder whether they made a mistake in concentrating so much of their firepower over the last week on the Liberal Democrats, thereby giving them the oxygen of publicity for which Charles Kennedy's party constantly craves.

However, our poll suggests that, if it were credible, the suggestion that a Liberal Democrat vote might result in a Conservative government would appear to be a potentially powerful one.

Nearly half of Liberal Democrats supporters, 49 per cent, say they will be unhappy if the Conservatives were to win today. Just eight per cent say they will be happy. In contrast, nearly as many Liberal Democrats, 27 per cent, say they will be happy if Labour win as say they would be unhappy (30 per cent). Many Liberal Democrat supporters evidently do not want to wake up tomorrow to pictures of a victorious Michael Howard.

Meanwhile, the Liberal Democrat vote is relatively soft. Liberal Democrat supporters exhibit even less determination than Labour voters to go to the polls; Just 72 per cent are certain they will vote, compared with 78 per cent of Labour supporters and 84 per cent of Conservatives. Even more strikingly, more than one in three of them also say that they could change their mind, far higher than the just over one in five of Conservative or Labour supporters who say they might still switch.

Moreover, if some of these uncertain Liberal Democrat voters were to switch, Labour would be more likely to be the principal beneficiaries. While 24 per cent say they could vote for the Conservatives, no less than 45 per cent say they would back Labour. All in all, it would seem as though Labour's attack on the Liberal Democrats ought to have worked - and of course might well have done so since NOP stopped polling on Tuesday.

But there is a catch. For while the Liberal Democrats may be in danger of losing voters at the last minute, they also have the prospect of gaining them, too. For nearly half of those Labour and Conservative voters who say they might switch say that if they did so they would back the Liberal Democrats. In combination, these potential switchers to the Liberal Democrats easily outnumber the potential defectors. So any tactic that enhances the credibility of the Liberal Democrats in voters' eyes can easily backfire.

In any event the overall pattern among those who might still switch suggests that, if anything, the Liberal Democrat vote is more likely to be higher than the 23 per cent figure in our poll than below it.

Nevertheless, unless the party does particularly well in its target seats, there is unlikely to be a large number of Liberal Democrat gains. Our projection of 62 seats is just 10 above what the party won last time around. Of the shadow cabinet ministers whose seats the party is hoping to win, only Oliver Letwin's Dorset West is clearly in danger. But even if this were all the party were to achieve, it would still be enough to give it its highest tally of seats since 1923. Nevertheless, if Labour wins another comfortable majority, it will still be a long way from power.

John Curtice is Professor of Politics, Strathclyde University