The First Minister’s dramatic announcement on Monday that she would now seek the authority to hold a second independence referendum in either autumn 2018 or spring 2019 was preceded by two new polls of referendum voting intentions. The first came from Ipsos MORI for STV News last Thursday, the second from BMG Research in The Herald just hours before the First Minister spoke.

Between them the two polls added some weight to the suggestion that the balance of opinion on the independence question may have narrowed somewhat since Theresa May outlined her vision of independence in a speech given at Lancaster House in mid-January.

The more eye-catching of the two came from Ipsos MORI. This poll actually put Yes very slightly ahead – by 47% to 46% – amongst those who say they are more or less certain to vote in an independence ballot. It was the first poll to put Yes ahead since three polls conducted in the immediate wake of the Brexit referendum last June. As it happened, however, once those who said they did not know which way they would vote were left to one side, the numbers actually came out as a draw – 50% Yes, 50% No – when reported to the nearest whole number.

The poll could, though, be regarded as rather less striking than it seemed. Ipsos MORI have a record of producing relatively high levels of support for Yes. When the company previously polled in September last year they found 48% support for Yes, whereas no other company polling at around this time put the figure above 47%. Meanwhile, two polls of referendum vote intentions that the company conducted between September 2014 and June 2016 actually put Yes ahead, in one instance by no less than 55% to 45%, when nearly every other poll was putting No ahead.  Taken together with the fact that the two-point swing in favour of Yes (as compared with September 2016) in the latest poll is not statistically significant, on its own the poll could be regarded as at best no more than a straw in the wind that there might have been a swing to Yes.

BMG, in contrast, put No ahead – by 52% to 48%. This actually represented a (insignificant) one-point swing to No since the company’s previous poll at the end of January, which in reporting a 49% vote for Yes had created quite a stir when it was first published. However, it still represented an increase in Yes support as compared with two polls conducted by the company in October and December last year, which (once Don’t Knows were left to one side) put support for Yes at 45% and 46% respectively. So here, perhaps, is rather more consistent (if a little less dramatic) evidence that the No lead might have narrowed somewhat.

If we take all five of the polls that have been conducted so far this year, on average they have put Yes on 48%, No on 52%. This compares with an average of Yes 46%, No 54% in nine polls conducted between July and December last year. Mind you, the latest figures still only represent a one-point increase in support as compared with the average of all of the polls conducted in the first half of last year up to EU referendum day. If the Brexit debate has begun to move the balance of opinion on independence at all, it has so far, at least, apparently only done so marginally.

Moreover, the Ipsos MORI poll contained a clear reminder that the degree of enthusiasm for Scotland staying in the EU may well be much less than might be anticipated from the fact that 62% of Scots who voted in the EU referendum voted to Remain. Rather less than half (48%) told the company that an independent Scotland should be a full member of the EU, while as many as 44% seem to be opposed to EU membership (27% stated that Scotland should have ‘full access’ to the single market without being a member of the EU, while 17% answered that Scotland should neither be part of the single market nor of the EU). Even amongst those who said they would vote Yes in a second independence referendum, only 64% backed the idea of EU membership – much as only two-thirds of Yes voters backed Remain last June.

It was perhaps revealing that the emphasis in Ms Sturgeon’s announcement on Monday was on keeping Scotland in the single market rather than in the EU. Perhaps she has been reading the latest polling very closely too!

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.