A third post-leaders’ debate poll of voting intentions in the referendum has appeared this morning. Undertaken by Panelbase for the Yes Scotland campaign, it casts further doubt on the proposition that the debate had an adverse impact on the Yes vote.

The poll puts Yes on 42%, up one point on the company’s previous poll for The Sunday Times in July, while No are on 46%, down two. Once the 12% who say they are undecided are left aside, Yes are on 48%, Yes on 52%, representing a two point swing to Yes.

Leaving aside a much criticised poll conducted by Panelbase for the SNP a year ago, today’s 48% for Yes equals the record high Yes vote in any Panelbase poll (after Don’t Knows are excluded) – the figure was previously recorded in a poll conducted by the company for the Yes campaign in June. Only one other poll has ever put the Yes vote so high – ICM for Scotland on Sunday in April.

Still, this does mean that today’s 48% vote is not unprecedented, while the changes in support since Panelbase’s previous poll are small enough that they could have occurred by chance. Caution is thus in order before we presume that today’s poll constitutes any evidence of new momentum towards Yes.  Indeed the publication of both this poll and today’s ICM poll for Scotland on Sunday leaves our poll of polls unchanged at Yes 43%, No 57%.

However, the fact that both this poll and ICM’s poll strongly suggest that the Yes vote has not declined in the wake of the leaders’ debate means that a pro-independence campaign that had appeared to be at risk of being written off by the media will now enter the last month of campaigning with renewed heart – and that interest in and speculation about the outcome of the referendum will remain at fever pitch.

Doubtless some will be inclined to raise questions about how it is that a poll conducted for the Yes campaign itself has now for a second time put the Yes vote at a record high. However, the method used in these two polls is the same as that used by Panelbase in its polls for The Sunday Times, a newspaper that is hardly a bastion of nationalism. It is simply the case, as regular readers will know, that Panelbase have persistently tended to produce the highest estimates of the Yes vote ever since polling of referendum voting intentions began in February of last year. Doubtless it is that fact that helps explains why the company has become the Yes side’s favourite pollster.

Meanwhile, we might now also wonder why it is that the first regular poll to be conducted after the leaders’ debate – by Survation –  showed a four point drop in Yes support, but that how we have had two polls that have registered a small if insignificant movement in the other direction. One possibility is that the random variation to which all polls are subject just happened to generate an unusually large swing when in fact nothing had changed. The other is that the debate did have a short term impact on Yes support, but that this loss was soon reversed once the memory of Mr Salmond’s less than commanding performance began to fade.

Today’s poll also contains a few additional questions that are clearly designed to generate favourable publicity for the Yes side. First it shows that more people think that each of Alex Salmond, Nicola Sturgeon and Dennis Canavan (the chair of the Yes campaign) stands up for the interests of Scotland than think they do not, while the opposite is the case for each of David Cameron, Alistair Darling and Johann Lamont.  Second, more voters say that ‘the prospect of an increased role of the private sector in the NHS in England having an adverse effect on the Scottish budget which funds NHS Scotland’ makes them likely (to vote for independence (46%) than say it makes them unlikely (35%) to do so. Of course, what matters is whether voters believe that that is the prospect that faces the NHS  if Scotland votes No – but perhaps we are about to see further efforts from the Yes campaign into persuading us that that is indeed the case.

About the author

John Curtice is Professor of Politics at Strathclyde University, Senior Research Fellow at ScotCen and at 'UK in a Changing Europe', and Chief Commentator on the What Scotland Thinks website.