Another new opinion poll, another new future. In this version of things-to-come, Labour would overtake the SNP at Westminster and Holyrood to become the dominant force once more in Scottish politics, with 40 MSPs and 28 MPs. Labour back on top. Labour the big boys again. Labour in charge.

But is that the future, or merely a reanimation of the past? For most of my life, even in the Tory-leaning north-east where I grew up, voting anything other than Labour was the sort of thing that made you an outlier and, in most places, the sort of thing that was a complete waste of time too. In more recent years, the same thing’s applied to the SNP, one monoculture replaced with another. What we need is a bit of biodiversity.

But what will we get? According to the new poll, which was carried out by Norstat for The Sunday Times, the SNP would hold on to just 15 of their 43 seats at the general election. At Holyrood, they’d get slightly more support but according to analysis of the polling by Sir John Curtice, Labour would still become the largest party there too. The question now, says Sir John, is whether the election of John Swinney will enable the SNP to turn the page.

Good question. I spoke to Sir John the other day about all of this and the subject of trends returning from the past came up quite a bit. Specifically – because his record for predicting the political future is so very good – I asked him where he thought we were going this time. Sturgeon gone, Yousaf gone, Tories in freefall, Labour on the rise. In some ways, this feels like 1997 again: a big old turnaround. So is that where we’re headed?

Sort of. Sir John was definitely up for talking about ’97 because it’s the subject of an event he’s doing at the Boswell Book Festival in Ayrshire this weekend. But he was also keen to point out that, although the current situation has some similarities to Blair’s first big victory (government party divided, political reputation trashed, opposition on the rise) there are serious differences too. Be in no doubt, Labour’s going to win the election, but the interesting bit is why, and how.

One of the biggest factors is Tony Blair himself. In some ways, Sir John believes it wasn’t actually Blair wot did it in ’97 – had John Smith lived, he says, Labour would have won anyway, so unpopular were the Tories. But he does point out that Blair was able to generate a sense of enthusiasm for his party in a way that Keir Starmer can’t, and Humza Yousaf can’t. So there isn’t the overwhelming passion for Labour there was in ’97 and the English local election results would seem to prove that. The lack of passion will undoubtedly affect things in Scotland too.

But assuming a win for Starmer at the general election – and Sir John has said there’s a 99% chance of it happening – I asked him if he was able to put a percentage on Anas Sarwar becoming First Minister. Too early, he said, and for good reason: Labour will be coming into power against the backdrop of an economy that may still be stuttering and lo and behold public services may continue to struggle and they’ll have to put up taxes. Give that another couple of years and Labour (and therefore Scottish Labour) may be none too popular by the time of the next Holyrood election, considerably damaging Mr Sarwar’s chances.

How things will pan out at the general election is also up for grabs. Effectively at the moment, there’s a battle going on about how to frame the election north of the border. Labour want to sell it as “you want to get the Tories out, therefore vote for us” whereas the SNP is saying “if you want independence, you need to vote for us”. In fact, it’s much simpler than that: it’s Labour that’s taking votes off the SNP so it’s Labour the SNP need to focus on and to a great extent the result will depend on how well they can do this.

The problem according to Sir John is there are a number of serious drags on the SNP’s ability to do the job. Firstly, the party is divided (and John Swinney may or may not be able to fix that). Secondly, the constitutional question that’s worked in the SNP’s favour does not dominate Scottish politics in the way it once did. And thirdly (and some might say about time too) more voters are making the connection between the state of hospitals, schools and so on and the SNP.

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The result is the emergence of a new species of voter: voters who until recently were pretty firmly SNP but are now willing to break away and vote for Labour. Some of them are probably doing it not because they’re passionate about Labour 1997-styley, but because they feel like they have no choice – the Tories are terrible, the SNP are terrible, so we might as well give these guys a chance. Also significant is the fact that something similar isn’t happening on the unionist side; Tory or Labour supporters going across to the SNP in any significant numbers just isn’t going to happen, John Swinney or no John Swinney.

All of this lays the groundwork for a bad general election for the SNP. As Sir John pointed out after the poll at the weekend, even among those who reported they’d vote Yes in another referendum, only 56% of them said they’d be willing to support the SNP for Westminster. This is a new development and means the projection of the SNP going from 43 seats to 15 is perfectly possible-slash-probable-slash-it’s going to happen isn’t it?

The longer term? Less certain. Sir John told me there was a time when politics in Scotland had almost become like it was in Northern Ireland: completely polarised. But that’s now fractured somewhat and what that means for the general election is becoming increasingly clear: Labour dominance, possibly including Scotland.

But the recent polling shows something else as well: it shows support for independence is still high at 48%, and that’s a strong base on which to build. Undoubtedly, the deflector shield of independence is no longer what it once was. But if and when Labour stumble (and they will) and if and when the SNP find a good leader again (and they will), it could be deflector shields on max again captain. It could be game on.

Sir John Curtice is at the Boswell Book Festival on May 11 at 6.30pm