The election is three days away but we already know the result. Labour, with a thumping great majority.

The Conservatives will suffer on two main fronts, with a chunk of their 2019 voters switching to Labour and another chunk going Reform. (A third chunk, I suspect, will simply stay home.)

The scale of defeat forecast points to a long sojourn in opposition, as the Tories attempt to rebuild their shattered electoral coalition. We might be talking decades rather than years.

Hell slap it into them, many will say. Look at the state of things after 14 years. They couldn’t run a bus to Blackpool let alone a country.

Traditional Tory supporters are livid. Unprecedented levels of immigration, legal and illegal. Identity politics run amok in almost every institution and public body. A toxic cocktail of low growth, high taxes and big spending.

Many lifelong Conservatives are eager to punish their party at the ballot box. They have been let down badly. They have every right to feel angry. And make no mistake: the Conservatives are going to pay the price on Thursday.

Consequences

But punishing the Tories in England and punishing them in Scotland have very different consequences. The former gets Labour candidates elected, the latter helps Nationalist MPs cling on.

That’s the case in those constituencies where it’s a straight choice between the Tories and the SNP. Lend your vote to Reform and your Nationalist MP or candidate will be the beneficiary.

I say this not out of any fondness for the Tories but because it is the inescapable truth. There are five seats with a notional Tory majority under 5,000 and the SNP in second place and four seats where the inverse is the case.

The notionally Tory seats are Aberdeenshire North and Moray East; Dumfries and Galloway; Dumfriesshire, Clydesdale and Tweeddale; Gordon and Buchan; and West Aberdeenshire and Kincardine.

The notionally SNP seats are Argyll, Bute and South Lochaber; Ayr, Carrick and Cumnock; Moray West, Nairn and Strathspey; and Perth and Kinross-shire.

In each of these constituencies, the only way to beat the SNP is to vote for the Conservative candidate. That might sound unfair to long-time Tories who wish to cast a protest vote for Reform but first past the post has never been a voting system known for its fairness.

Where it’s close between the Nationalists and the Conservatives, there’s no avoiding the electoral reality: vote Reform, get SNP.

Take the seat of Perth and Kinross-shire. Before the boundary changes, it was called Perth and North Perthshire and the SNP’s Pete Wishart held it in 2019 with a majority of 7,550. But under the new boundaries, Wishart’s notional majority is slashed to 2,364, making him vulnerable to a strong Tory candidate.

The Tories, in a rare outbreak of good sense, have put up a strong candidate in the form of Luke Graham, previously head of the Downing Street Union Unit tasked with taking on the Nationalists. He has a solid record when it comes to taking seats from them, too. In 2017, he overturned an SNP majority of 10,000 to oust Tasmina Ahmed-Sheikh.

But he can’t unseat Wishart if Tories in Perth and Kinross-shire vote for the Reform candidate. Imagine being the Unionist voter who helps Pete Wishart hold on to his seat.

Candid

It is for every voter to make up their own mind, but it is vital to remember the context in which they must make that decision. John Swinney has been entirely candid: if the SNP wins a majority of Scottish seats he will resume the campaign for a second independence referendum. A majority is 29 seats. Every seat that stays or goes Nationalist gets him closer to that threshold.

For their part, the Scottish Conservatives have placed opposition to independence at the heart of their manifesto. That reflects the constitutional stance of a majority of people in Scotland but if the Tories are wiped out because of Reform, Swinney will say Scotland has rejected the anti-independence message.

Presented with a defence of the Union, all 57 Scottish constituencies voted for a different platform. It would be humbug but if there’s one thing the SNP excels at, it’s spin. And what a relief it would be to Swinney if Reform voters help the SNP hang on to more seats than expected. The First Minister’s coat will be on a shoogly peg if the Nationalists sustain very heavy losses. Another leadership election would plunge them into crisis. But they won’t have to worry if Conservatives swoop in to save them by putting their X next to Reform.

Picture it: Thursday night, BBC One, 10pm. Big Ben begins chiming and the exit poll flashes on screen. A whacking great majority for Labour, but then something else catches your eye. The SNP’s seat total. It’s higher than the polls forecast, and by a good margin. Every Tory seat in Scotland has gone yellow and in those where the SNP was vulnerable the incumbent Nationalist has clung on.

Victorious

It’s still not a happy night for Swinney’s party. They’ve been routed by Labour across the Central Belt, but have defied the direst predictions to come a respectable second. Then the declarations pour in and, in one SNP-Tory marginal after another, you watch a victorious Nationalist punch the air as the vote tallies are read out. In each, the Conservative candidate came achingly close but the Reform vote was too big – bigger than the SNP’s majority.

It hits you like a punch in the gut. You voted Reform to send the Tories a message. You didn’t mean to help the SNP. You don’t have long to process these thoughts before the camera cuts to your Nationalist MP and soon he’s saying that his constituents have voted to restart negotiations for indyref2. No one could dispute that: after all, it was page one, line one, of the SNP manifesto.

As you watch, you become increasingly glum. It’s that look on your MP’s face, relief giving way to smug triumphalism. He only survived because disaffected Tories went over to Reform. And now he and his colleagues are going to spend another five years banging on about referendums, mandates and rejoining the EU.

You reach for the remote but before you can hit the off button, you hear a pundit remark on the irony of the Scotland results: the SNP was heading for a wipeout until Unionist voters stepped in and rescued them.

If that happens on Thursday night, it will go down in Nationalist lore. It was the election in which independence was on the brink of irrelevance for a generation – a real generation, this time – but Unionists kept the SNP’s dream alive. And they did it by voting Reform.

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