Gamble to back early election has paid off with Labour weakened and Tories likely to further alienate Scottish voters

A short walk from the Houses of Parliament, Scotland’s newest MPs gathered on Monday afternoon to celebrate another Scottish National party landslide. Many of the 47 MPs wore the party’s logo on their lapels, and others the party’s bright yellow on coats and scarves.

“We stood on a clear and unequivocal platform of rejecting Brexit and giving the people of Scotland a choice over their future – ensuring Scotland’s future is in Scotland’s hands,” said Ian Blackford, their Westminster leader.

In a break with tradition, Nicola Sturgeon was not there to relish the moment. She stayed in Edinburgh to immerse herself in the work that last week’s election had delayed, work now dominated by one topic: independence.

This week Sturgeon will publish a new document she hopes will define the case for independence and strengthen her demands for the powers to stage a second referendum.

On Thursday a separate bill is due to be voted through at Holyrood setting out how referendums in Scotland will be run. For supporters of independence there is now an inescapable sense of momentum, and of an opportunity greater than in 2014 when they fought and lost the first referendum.

Sturgeon sketched out her case six hours after the last Scottish seat was declared. Her party had seized 80% of Scotland’s seats. In every recent election, she said, Scotland had voted differently from the rest of the UK. It was a question of accountability and democracy, a “watershed moment”.

On Sunday Sturgeon intensified the rhetoric, declaring on the BBC’s Andrew Marr Show that Scotland could not be “imprisoned in the UK against its will”.

Alongside publishing her referendum paper, Sturgeon will write formally to Boris Johnson asking his government to give Holyrood the legal powers to stage an independence vote. Johnson told Sturgeon on Friday he would refuse, setting up a constitutional standoff that could end in the courts.

For the independence movement, last week’s election reinforced its frustration with the UK’s constitutional arrangements. A rightwing Conservative government led by an old Etonian won a landslide victory gifted by English voters. In Scotland the Tory vote fell by 3.5 percentage points and the party lost seven seats.

With an 80-seat majority, Johnson is now able to force through Brexit, a policy rejected by Scottish voters in 2016, when 62% backed remain, and last week, when 75% of the Scottish vote went to parties opposing his plans.

Like Johnson, Sturgeon gambled that the snap general election would bolster her party’s position. Alongside the Liberal Democrats, the SNP at Westminster pushed Jeremy Corbyn into supporting it. The gamble paid off, delivering her a better result than expected. In a repeat of 2015, Labour was left with one Scottish seat. In 2010, when Gordon Brown was Labour leader, it won 41.

Facebook Twitter Pinterest The SNP’s Westminster leader, Ian Blackford, with the party’s MPs outside parliament. Photograph: Tolga Akmen/AFP via Getty Images

Some Scottish Labour figures, badly bruised by yet another humiliating election result, endorse Sturgeon’s arguments about Scotland’s right to choose.

Kezia Dugdale, who quit as Scottish Labour leader largely due to Corbyn’s ambivalence on Brexit, tweeted that pro-UK campaigners were “wasting precious time” arguing about Sturgeon’s mandate. Their arguments in 2014 that Scotland could be assured of a progressive Labour government and continued EU membership through the UK had “melted away” on Friday, she said. “You need a new argument for the union which isn’t rooted in Queen and country unionism,” she said.

Sturgeon has been choosing her language carefully, framing the case for a referendum around choice. To her frustration, Westminster’s chaotic handling of Brexit and Johnson’s subsequent election as Tory leader has not led to a surge in support for independence.

The polls show support averaging around 48%. The latest poll by YouGov for the Times the week before the election found a five-point fall in the yes vote, down to 44% excluding don’t knows.

Last week’s election arguably produced a majority of votes for anti-independence parties: the Tories, Labour and Lib Dems won 54% of the vote. (The pro-independence Scottish Greens took 1%.) Sturgeon acknowledges that many votes the SNP attracted last week were pro-EU, including from former Labour voters disillusioned by Corbyn’s record on Brexit.

The intersecting issues at stake in this election mean it is impossible to read the SNP’s success as an unambiguous endorsement of independence. Some voters may have backed the party without sharing its commitment to going it alone in the end. Sturgeon told Marr on Sunday: “I don’t presume everyone who voted SNP on Thursday is yet prepared to back independence … but it’s for the people of Scotland to decide.”

But the polls also show evidence of a potential yes vote ready to be tapped. Several this year have said the combination of a Johnson government and Brexit could nudge the yes vote above 50%. There is higher support for holding a referendum, and polls that ask the question show a majority of Scots expect independence to take place over the next decade. Thanks to the new referendum bill, EU citizens in Scotland would be able to vote too, which is expected to boost the yes vote.

Sturgeon’s challenge is converting that potential into concrete support. The largest reservoir to tap is pro-EU voters – most likely Labour or Lib Dem supporters – who voted no in 2014.

The first minister believes that a Johnson government pushing through illiberal policies that challenge centrist norms valued by Scottish voters – in areas such such as the welfare system, redistributive taxation and the BBC – will help her case. Johnson will continue investing in a new nuclear weapons system to replace Trident, which the UK government assumes will be based, like Trident, at Faslane submarine base near Glasgow. That policy drives up the yes vote.

Johnson’s Brexit model will be another strong card. Sturgeon will focus on his decision to give Northern Ireland special protections, keeping it within the EU’s customs union and retaining an open border with Ireland, and will ask why Scotland does not get similar privileges. She will focus on any moves by the UK to dilute EU environmental, social or food standards rules.

Facebook Twitter Pinterest Anti-Brexit protesters in Glasgow in August. Photograph: Andy Buchanan/AFP/Getty Images

She will continue pressing the case for Scotland to have much greater say in UK immigration policy post-Brexit, and extra privileges tailored to Scottish needs, pointing at Scotland’s ageing population and workforce shortages. Scotland’s latest GDP figures are due to be published this week: if they again show a weakening economy, Brexit will be blamed.

Sturgeon’s opponents argue this is much trickier territory for the yes campaign than she will concede. The Scottish government is heavily dependent on Treasury subsidies for its spending, with public spending nearly £2,000 per head higher than the UK average, leaving an overall deficit in day-to-day spending equal to 7% of GDP, the highest in the EU.

Sturgeon will face searching questions about how an independent Scotland could maintain public services while driving down that deficit; whether there would be a customs border at Berwick and Gretna Green, with tariffs inhibiting trade with the rest of the UK; whether Scotland could continue using sterling as its currency and still apply for EU membership; and how Scotland could continue to afford to fund pensions without the UK’s financial support.

Sturgeon’s view is that it is all up for negotiation, and that much could be dealt with during a transitional period or by treaty. She has her own cards to play: she could trade the UK’s continued use of Faslane for preferential arrangements on debt and pensions, and the UK will still need Scotland’s significant renewal electricity output.

For now her strategists focus on building momentum. That will involve getting endorsements: lists of celebrities, well-known politicians and industrialists who have converted to independence or who simply endorse the right to choose are being prepared. Grassroots independence campaigns have marches planned.

Perhaps Sturgeon’s greatest asset is her enemies’ weakness. Who speaks for the union? There is no prospect now of a joint effort involving Labour, the Tories and Lib Dems replicating the Better Together campaign of 2014. With Johnson toxic in Scotland, the pro-UK campaign has no obvious message carrier. As Dugdale points out, the Labour party has failed to table a credible counter-offer.

Dugdale’s successor as Scottish Labour leader, Richard Leonard, had hoped there was time for the party to join the Lib Dems in embracing federalism across the UK. His timetable was ruined by the snap election, and Labour’s heavy defeat makes it far harder to persuade voters it can ever deliver an alternative.