It now seems highly likely that rather than clawing back some of its losses, Labour has in fact lost further ground during the course of the election campaign. That at least appears to be the implication of the latest Panelbase poll that appears in today’s Sunday Times.

Regular readers of this blog will be aware that within the last fortnight YouGov have twice recorded a record high SNP lead over the SNP, TNS BMRB have put the nationalists above 50%, while Lord Ashcroft has released constituency polling that suggests the swing to the SNP has grown since a couple of months ago. When some of this evidence first came through I suggested we should be cautious before jumping to the conclusion that the SNP vote had increased. Perhaps the movement reflected no more than the chance variation to which all polls are subject. But now Panelbase are the third company to give the nationalists a record lead, and this must pretty much dispel any remaining doubt that there has at least been some movement in the SNP’s direction.

Today’s poll puts the SNP on 48%, up three points on Panelbase’s previous poll conducted just before Easter, and no less than seven points on its reading before that in January. Labour, meanwhile, are on 27% down two points on the pre-Easter poll and four points on that in January. As a result of today’s poll, Labour’s reading in our poll of polls now stands at just 25%, lower than it has been at any time since the independence referendum.

It appears that one of the reasons at least why support for the SNP has grown is that those who voted for independence last September are now even more united in their determination to vote for the SNP. In the Panelbase poll back in January only 75% of those who said that they had voted Yes indicated that they intended to vote for the SNP. Now that proportion stands at 86%. There has in truth also been some increase in support for the SNP amongst No voters, but it has been on a smaller scale, from 8% in January to 13% now. Comparison of the two most recent YouGov polls with its two immediate predecessors tells a similar if somewhat less dramatic story.

Labour has tried to make hay in the last fortnight or so with the Institute for Fiscal Studies’ calculation that the introduction of what has come to be known as ‘full fiscal autonomy’ (though now renamed ‘full fiscal responsibility’ by the SNP), that is the idea that the Scottish Parliament should become responsible for taxation in Scotland (and thus for funding all public services in Scotland), would in the short-term leave a £7.6bn shortfall in Scotland’s public finances. It seems, however, that this claim has failed to hit home.

As we might anticipate from previous survey work on attitudes towards more devolution, the Panelbase poll finds that the idea of fiscal autonomy is relatively popular. Just 33% say that they oppose the idea, while 53% are in favour. Meanwhile, rather more people (39%) believe that Scotland as a whole would be better off under fiscal autonomy than believe it would be worse off (31%).

Unsurprisingly, SNP supporters are almost unanimous in their support for the idea. No less than 87% are in favour. However, it seems that Labour has been struggling somewhat to persuade its own supporters of its argument, let alone anyone else. Just 42% of Labour supporters say that they oppose full fiscal autonomy, only a little more than the 36% who say they are in favour.

Not least of the reasons for this failure, perhaps, is that Labour simply has the less appealing personalities in the eyes of voters. As many as 51% now say that they are satisfied with the performance of Nicola Sturgeon, up from 42% in January. In contrast only 23% are satisfied with Jim Murphy, little different from the 21% who were of that view in January. Meanwhile, although as in the Britain-wide polls Ed Miliband’s ratings have improved – 23% are satisfied with him now compared with 13% in January – that still leaves him well behind Nicola Sturgeon. And there is now very little time left for Labour to find a way of turning these perceptions around.