Now we know why Nicola Sturgeon resigned – SNP support has collapsed

It’s just one poll, but we can now see that the bottom had fallen out of Nicola Sturgeon’s world before she announced her resignation on Wednesday. A survey taken by YouGov in Scotland in the six days up to and including the day of her announcement has found that support for the Scottish National Party has slumped, while Labour support has doubled – at the expense also of the Tories and Lib Dems – putting Labour within touching distance of the long-dominant SNP.

Even if other opinion polls don’t show quite such dramatic changes, there is no doubt that something big has happened in Scottish politics. Ever since the referendum on independence nine years ago had the paradoxical effect of energising the losers and dividing the winners, the question has been: around which party will opposition to the independence movement coalesce?

For a while it seemed as if the Conservatives would have to step up and reclaim the Unionist part of their full name. The inherent implausibility of this, given the way anti-Tory sentiment suffuses the tiny world of elite Scottish politics, was briefly overcome by the brilliant and un-Tory leadership of Ruth Davidson, whose party won 13 Scottish seats in the House of Commons in 2017.

In the end, that was never going to work. If the SNP hegemony were ever to be challenged, it would have to be by Labour, the other party best placed to take advantage of Scottish anti-Toryism. And the party that only recently enjoyed the kind of dominance in Scotland that the SNP supplanted.

It was remarkable that Sturgeon, in her resignation speech, actually used the word, saying: “It has always been my belief that no one individual should be dominant in any system for too long.” Well, she isn’t now, and her party may not be for much longer either. If the next general election is competitive between the SNP and Labour, then Keir Starmer can hope to start to overcome one of the structural barriers to a sustainable Labour government of the UK.

Since Labour’s wipeout in Scotland in the 2015 general election, the absence of a reliable block of its MPs sent to Westminster has long made a majority Labour government look like a distant prospect. Suddenly, it is nearer again.

This is most unfair. Starmer was so naive about Scottish politics when he ran for the Labour leadership that he fell for the superficially plausible line that of course the SNP should have another referendum if pro-independence parties win a majority in the Scottish parliament. He quickly realised that this was a mistake. It would raise the spectre of Labour and the SNP working together to break up the UK in a hung parliament after the next Westminster election. So he hurriedly changed his language to “now is not the time” for another referendum and “no deals with the SNP under any circumstances”.

It was the strategic patience of the Conservatives, though, that did most to saw the circle from underneath the stage on which Sturgeon stood. Even Boris Johnson worked out that boisterously playing the pantomime villain was counterproductive. He developed the soft line of not saying “no” to a second referendum, but pointing out that the Scottish people thought other things were more urgent. He remained personally unpopular in Scotland – he was almost as unpopular as Alex Salmond – which kept the fires of anti-Toryism burning.

So the switch to Rishi Sunak was the beginning of the end for Sturgeon. He is a Tory, so most Scots don’t like him either, but he offered far less fuel to keep the SNP machine going. He simply refused to engage with SNP MPs in the Commons, thanking them for their questions and offering to work with them for the benefit of the people of Scotland.

Without the outrage of “Boris”, the dead end in which the independence movement had found itself was cruelly exposed. Sturgeon had done a remarkable job for eight years of giving her supporters – and her opponents – the impression that independence was just around the corner. But suddenly, without the Johnson bluster around, it became more obvious that her project had no visible means of support.

That is not to say that Starmer, after his early misstep, has not shown some ruthless political instincts. He engineered the ousting of the Corbyn-adjacent Richard Leonard as Scottish Labour leader two years ago, and his replacement by Anas Sarwar. Sarwar has also played a tricky hand well – even if he and his party ended up, with Sturgeon, on the wrong side of public opinion on the gender recognition bill.

Now Sarwar and Starmer are poised to make the kind of advances in Scotland that could make all the difference to the chances of a sustainable Labour government of the UK. And the more likely a UK Labour government becomes, the harder life gets for the SNP, as the great engine of Scottish anti-Tory sentiment stalls.