Gordon Brown remains in a very deep hole; David Cameron is climbing his electoral mountain but is still a long way from the top; and Nick Clegg now realises how long a journey he faces. The latest Populus poll, the first of the new year, provides a jolt of reality for all three main parties.

The poll punctures the naive euphoria of some Tory MPs and commentators in mid-December - never shared by Mr Cameron - when the party touched 43 to 45 per cent and was said to be heading for an overall majority. That was always frothy and, in line with two other recent polls, Populus now shows a halving of the Tory lead.

What matters is the level of party ratings, with the Tories down three points at 37 per cent, entirely because of a three-point boost to the Liberal Democrats, up to 19 per cent, their highest since last April. This initial Clegg bounce underlines how important it is for the Tories to squeeze the Lib Dems.

There is nothing for Labour to celebrate. Its 33 per cent, up one point, is barely above its low point of early last year. All three parties are more or less where they were a year ago. Moreover, Mr Brown’s personal ratings are dire. His leader index (on a scale of 0 to 10) has fallen sharply (by 0.89 points to 4.60) since late June, just after he became Prime Minister. Tony Blair’s rating only once went lower, in July 2006. By contrast, Mr Cameron’s leader index has risen by 0.26 points to 5.07, the highest of the three party leaders, but slightly below a year ago. His rating among Tory supporters has risen from 6.65 to 6.81, just above Mr Brown’s among Labour voters.

Even more worrying for Mr Brown is the very big, and continuing, shift in ratings on leader attributes in favour of the Tory leader. For instance in July, 71 per cent regarded Mr Brown as strong, against 39 per cent for Mr Cameron: now the balance is 55 to 49 per cent. Similarly, six months ago Mr Brown had a 56 to 32 per cent edge over Mr Cameron in having what it takes to be a good prime minister: now the Tory leader is ahead by 44 to 40 per cent. Half of this shift has occurred in the past two months.

There have been similarly big swings against Mr Brown on being more honest than most politicians; having his party’s backing; caring about ordinary people’s problems; and sticking to what he believes in. Mr Cameron is a long way ahead on charisma and likeability.

Despite the rise in Lib Dem support, the key finding for Mr Clegg is that about two fifths of voters do not yet know enough about him to take a clear view (compared with only 9 per cent for Mr Cameron and 5 per cent for Mr Brown). That is why not too much should be read into his initial leader index of 4.40, fractionally above the last one for Sir Menzies Campbell. But Mr Clegg’s rating among Lib Dem supporters of 6.5 is well above his precedessor’s last one of 5.63 in July. Mr Clegg’s ratings on leader attributes are below Sir Menzies’s but, again, up to a half of voters are don’t knows.

Mr Brown cannot brush aside this poll by invoking the long term. His reputation has been badly damaged by his recent troubles and mistakes. There are no signs of recovery.

Populus interviewed a random sample of 1,509 adults aged over 18 between January 4 and 6. Interviews were conducted across the country and the results have been weighted to be representative of all adults. For more details go to populus.co.uk.

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