The honeymoon is far from over as Salmond’s stock keeps rising

The Labour and Liberal Democrats ejected from office last May are both going backwards, with the UK picture showing a post-Budget slump for Labour who are trailing the Tories by 16 points.

That is the widest margin for 21 years, though with little sign of that boosting Scottish Conservative fortunes.

This rare evidence of Scottish public opinion shows Salmond out-polling Wendy Alexander by a colossal margin. Their favourability ratings, taking the negatives from the positives, put him 53 points in the black, while the Labour leader is 22 points in deficit. She clearly trails the First Minister even among Labour voters.

This comes less than two weeks before the first Scottish Labour party conference since it lost power, with Ms Alexander's own six months as leader facing criticism along with significant doubts about her future.

Much of the public perception of her leadership results from media reporting of her campaign fundraising, which broke the law, so perhaps the surprise is that as many as 30% of people think she is doing a good job as leader. It will not help that new allegations were published yesterday, saying her Holyrood allowances were used to support her leadership bid. Such stories have led 40% of those polled to be less likely to support Labour, and a minority think she should quit.

However, the MRUK poll carries a warning to the SNP. Support for independence, at 23%, is unusually low. Only one other poll has found it that low in recent years. With 45% preferring the devolved parliament to continue but with more powers, it shows the SNP could be proving so adept at running a devolved administration that it undermines its own case for an independent one.

In the coming weeks ministers are to highlight the difference they are making in an advertising campaign starting this week, drawing attention to the falling cost of prescriptions, the council tax freeze and reduced business rates.

Another clear message from the poll is that much of the SNP's strength is in its leader, whose favourability ratings - 70% say he is doing a good job, with 17% saying the opposite - are far ahead of support for his party. When pollsters asked those who do not support independence what might persuade them to do so in future, Mr Salmond's persuasive skills were one of the two top factors.

While a hypothetical polling question from part of a sample should be taken with a bigger pinch of salt than usual, another 29%, said they may change their minds if Scotland's share of public spending is cut by the Treasury.

Within that group, 24% of people could be persuaded to support independence by the election of a Tory government at Westminster, while 20% could be persuaded by the re-election of Labour. That shows people are already open to persuasion about the case for independence, and whatever the outcome of the next election, due by spring 2010, more people will be persuadable.

It also shows the Conservative Party may be shaking off its electoral disadvantage in Scotland. It has been assumed the return of a Tory prime minister, backed by a large English vote, would drive more Scots to support autonomy.

But it seems the prospect of David Cameron in No 10 Downing Street would not have much more impact on Scottish public opinion than Gordon Brown's re-election.

Scottish Tories should worry, though. The Scottish data, collected from 1028 people nearly three weeks ago, shows their support down slightly on a poor result at last May's election, leaving a stark contrast between Annabel Goldie's fortunes and those of David Cameron.

A separate poll, published yesterday and researched by YouGov since last Wednesday's Budget, put Tories throughout Britain on 43% while Labour is on 27%. Despite being a fresh face as LibDem leader, Nick Clegg is failing to turn around his party's polling fortunes, with only 16% support.