What are the chances of a Labour-SNP pact after December 12?

No 10 Downing Street, primed for a full term in office and ready to trigger Brexit at the earliest possible opportunity.

Or Jeremy Corbyn will be on the brink of becoming prime minister, at the head of a minority Labour government, buoyed by the support of 40 or 50 Scottish National Party MPs.

In the event of a hung parliament, all eyes turn to Nicola Sturgeon. To what extent can the SNP leader work with Corbyn? To what extent can he work with her?

Relations between the Labour and the SNP have been tense throughout this election campaign.

Sturgeon has repeatedly attacked Corbyn over his handling both of Brexit and the anti-Semitism controversy that has dogged Labour in recent years.

“I don’t choose the leader of the Labour Party,” Sturgeon said at the launch of the SNP manifesto in November. “I wouldn’t choose Jeremy Corbyn, but I’m not in charge of that decision.”

Labour have been equally pointed in their approach to the SNP.

Speaking to the New Statesman earlier this week, the shadow chancellor John McDonnell said his party wouldn’t authorise a second independence referendum – the SNP’s core demand ahead of any post-election negotiations with Corbyn – until after 2021, and only then provided there’s a pro-independence majority in the Scottish Parliament.

Should Sturgeon reject that offer, Labour will present a Queen’s Speech to the Commons and dare SNP MPs to vote it down.

“Let the SNP vote against a real living wage, ending austerity, investing in the NHS,” McDonnell said. “Let them try it. But if they did, we’d go back to the people and they’d be annihilated.”

Perhaps we shouldn’t be surprised that Corbyn and Sturgeon don’t get along: they hail from different ideological traditions.

Corbyn is a veteran socialist, rooted in extra-parliamentary campaigning, whose politics are guided by an unambiguous set of moral principles.

Sturgeon is a managerial social democrat whose experiences running the Scottish Government mean she is accustomed to the compromises of power.

And yet, despite their contrasting political styles, the two leaders agree on a huge number of progressive policies, from the abolition of the House of Lords and raising the minimum wage to repealing Thatcher-era anti-trade union legislation and slashing carbon emissions.

If Johnson fails to win convincingly on Thursday, these are the sorts of positions that could form the bare bones of a functioning confidence-and-supply agreement between Labour and the SNP at Westminster.

Boris Johnson is in trouble if he fails to secure a majority

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Labour would present its budgets before parliament and the SNP would ensure they secured legislative assent – with the proviso that Scotland would soon be granted another referendum on the break-up of the UK.

The respective Labour and SNP leaderships may view each other with a high degree of mutual distrust, but the acrimony is less acute outside party elites.

“The most effective way of getting Corbyn into No 10 at this election is to vote for an SNP MP,” one prominent nationalist candidate told me at the outset of the election campaign. “Labour’s policies are a lot more forward-thinking than the Tories.”

Another SNP source acknowledged that there was real space for co-operation between the two parties – particularly on a second Brexit referendum, which both Corbyn and Sturgeon are signed up to.

“Where there is common ground and the capacity to get something done, let’s do that,” they said.

In reality, Corbynism and support for Scottish independence have a lot in common beneath the surface.

Both are symptomatic of Westminster’s failure across a range of social, economic, and constitutional fronts.

Both attract disproportionate amounts of support from people under the age of 35.

Both embrace a belief that London, as a financial and political capital, is too powerful.

And both provoke regular howls of outrage from the UK right.

In April, Tory minister Priti Patel branded Corbyn “the most dangerous man ever to lead a British political party”, echoing sentiments first expressed about Sturgeon four years ago in the pages of the Daily Mail.

Younger Corbyn supporters are conscious of the parallels between the independence movement and the Labour left.

Indeed, several influential Corbynites were enthusiastic about independence in 2014 and saw the Yes campaign as a popular revolt against austerity in the wake of the global financial crisis.

John McDonnell's politics share similarities with the independence movement's

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CORBYN’S 2015 bid for the Labour leadership “didn’t come from nowhere”, James Schneider – a journalist who helped set up the campaign group Momentum before being appointed Corbyn’s head of strategic communications – told Jacobin magazine in 2016.

“We had seen Occupy, Greece and Spain, the Scottish referendum, and we just felt that this was our one,” he said.

Labour’s growing willingness to facilitate indyref2 reflects a degree of pre-election jockeying.

But it also highlights how profoundly the party has changed since Corbyn’s ascendancy.

In contrast to Tony Blair and Gordon Brown, Corbyn and McDonnell are not ideological Unionists. They don’t believe in the inherent supremacy of British institutions or embrace Britishness as an essential part of their political identity.

The Union is justified only in so far as it can be used to promote socialism throughout the UK. Beyond that, it is largely expendable.

The same can’t be said for Scottish Labour, of course, which has become increasingly defined by its opposition to independence over the past decade or so.

The right of the party is already furious about the prospect of a post-election deal with the nationalists.

The idea of a Labour prime minister working with the SNP is “genuinely idiotic”, former Better Together chief Blair McDougall told The Times this week.

“It’s like sitting on a branch and doing a deal with the guy who is sawing the branch. It makes no sense.”

Several factors might help mitigate Scottish Labour’s opposition to a Corbyn-Sturgeon pact.

Some Scottish Labour activists are trying to overhaul the party’s

approach to constitutional politics by striking a more conciliatory tone

towards independence supporters

“If we can prove that we have genuinely changed, have a respectful attitude to self-determination, and have a meaningful programme to transform Scotland, we can start peeling working-class and left-wing voters away from the SNP,” one such activist told me.

“But for voters to cross that bridge, we have to build it first.”

Recent changes to Labour’s membership structure and internal personnel in Scotland could accelerate the party’s shift away from the Union.

“The biggest visible change [to the party since 2014] has been the appointment of election organisers who voted Yes,” another Scottish Labour source said.

“Large numbers of the younger activists chapping doors for Labour at this election are Yes voters who want to elect a Corbyn government.”

Scottish Labour can’t escape the fact that its embrace of hardline Unionism has been electorally disastrous, either. The party finished fifth, with less than 10% of the vote, at the European elections in May, trailing both the LibDems and Nigel Farage’s Brexit Party.

And if current polls are to be believed, it stands to lose all but one or two of its seven Scottish seats on Thursday.

Edinburgh South is pretty much guaranteed to re-elect Ian Murray and Leslie Laird’s chances of holding Kirkcaldy and Cowdenbeath have significantly improved since the suspension of Neale Hanvey as the SNP candidate in that constituency.

Labour’s decline in Scotland reflects a deeper shift in Scottish public opinion.

Lesley Laird appears to be in with a good chance of reclaiming her seat

ACCORDING to a Panelbase poll released at the end of November, 49% of current Scottish Labour voters support independence, while up to 70% of young Scots say they would vote for independence in another referendum.

Given these trends, it’s difficult to see what Richard Leonard – or his successor – would have to gain from trying to block Corbyn and the SNP joining forces in the Commons.

And if he did, there’s a good chance Scottish Labour would slip further into obscurity at the next Holyrood election in 2021.

That said, assuming Labour and the SNP can put their tribal differences to one side and reach a deal after December 12, the new arrangement will likely have a short shelf-life.

“There’s scope for a rainbow group that can unite around a couple of common points – a second EU referendum, for instance,” one senior SNP source told me. “But I wouldn’t see it as workable in the long term.”

Ultimately, the Corbyn-Sturgeon alliance would probably break down along the unavoidable constitutional fault-line of independence.

Sturgeon wants another referendum during the later half of 2020.

Corbyn wants to hold off on indyref2 until the “later years” of his first term in office, in the hope that Labour’s expansive programme of public investment will chip away at Scottish working-class support for

independence.

But even if the two parties can only agree a momentary accommodation, the impact on Britain’s political landscape would still be immense. Boris Johnson would be gone.

Brexit would be reversed or renegotiated. The era of austerity would be over. And Scotland would have another opportunity to strike out on its own, forever altering the political and constitutional structures of the UK.