Nicola Sturgeon has been served notice: she can no longer take her supporters for granted

Scotland did things differently again. While England and Wales witnessed a return to two-party politics, in Scotland the election was won by the SNP. Equally whereas in England and Wales there was a swing from Conservative to Labour, in Scotland the Conservatives overtook Labour for the first time since 1959. Politics in Scotland retained the distinctiveness it has increasingly acquired in recent years.

That distinctiveness has largely been a product of the intense debate about how Scotland should be governed. And it seems clear that it was that debate that had more influence on the electoral outcome north of the border than the one about Brexit that was meant to be the focus of the election.

The first clue lies in the evidence of the final opinion polls, which broadly anticipated the eventual outcome. They found that those who voted Yes in 2014 and those who backed No differed much more in the way they were going to vote than did those who supported Remain and those who backed Leave.

On average, these polls found that nearly three-quarters (73%) of those who voted Yes were intending to vote SNP, whereas just one in eight (12%) of No voters were doing so. This gap is much bigger than the equivalent one between Remain and Leave supporters. Less than half (44%) of Remain voters intended to vote SNP, while just over a quarter (27%) of Leave supporters anticipated doing so.

The second indication lies in the existence of the Conservative revival. In England and Wales, the Conservatives performed best where Leave voters (and thus former UKIP voters) were most numerous. Yet despite the strength of the Remain vote north of the border, this did not stop the party increasing its vote by 14 points in Scotland, a much bigger increase than was recorded in any region of England or in Wales.

Thirdly, it seems that Labour and Liberal Democrat voters were willing to switch to the Conservatives where the party had established itself locally as best placed to defeat the Conservatives. In no less than nine of the dozen seats that the Conservatives gained, there were sharp falls in either the Labour or the Liberal Democrat vote. This suggests the motivation to inflict defeat on the pro-independence SNP mattered more to unionist voters than the differences between the unionist parties about what kind of Brexit the UK should be seeking.

We might imagine therefore that we should conclude that the decline in SNP support. from 50% in 2015 to 37% now, indicates that the independence bubble has burst. For if the election was primarily about independence then presumably any change in SNP support tells us something about support for Scotland going it alone. On this, however, we should be a little more cautious.

While Yes voters may have been much more likely to vote SNP than No voters, still only around three-quarters actually did so. This is well down on the equivalent figure recorded by the same pollsters two years ago; then no less than 88% of those who voted Yes said they were going to vote SNP.

Moreover, while support for independence in the polls is down a little as compared with two years ago, the apparent drop – of some three points to 44% - is far too small to account for the 13 point drop in SNP support. In any event, it still means that support for independence remains more or less at the level recorded in the 2014 independence referendum.

In short, the main reason for the decline in SNP support lies in the fact that fewer of those who say they support independence were willing to back the party.

One possible explanation for this pattern is that the reluctance that was evident before 2015 amongst some voters to back the SNP in a Westminster election in which the party can seem irrelevant has taken hold once more. Another is that the growing criticism of the SNP’s domestic record is taking its toll, even amongst independence supporters. Or it might be that the lack of enthusiasm that is evident amongst some Yes voters for a second independence referendum may also have cost the party votes.

But whatever the explanation, Nicola Sturgeon has been served notice that she should not take her supporters for granted.

Now read Adam Tomkin's on why Scotland is returning to left-right, rather than Yes-No, politics.