AS in 2017, have the SNP just been caught out by a surprise General Election announcement at the worst conceivable moment? If Sunak had fired the starting gun even a few weeks earlier, the SNP would not have just come through a traumatic coalition break-up with the Greens, followed by the enforced departure of Humza Yousaf. They would be starting the campaign roughly level-pegging in the polls with Labour, which would have left them with a good chance of rescuing dozens of their seats, thus keeping the independence flame burning bright.

As it is, the most recent polls place the SNP in their worst position in a decade. A Redfield & Wilton poll conducted on May 8 and 9 had the SNP on 31% of the vote for Westminster vote, seven points behind Labour. That would see them hold 12 seats, a mere quarter of the 48 they won in 2019.  Worse was to come from a YouGov poll conducted between the May 13 and 17, which suggested the SNP were on 29%, a full 10 points behind Labour and on course to be reduced to only eight seats.

The paradox is that both polls suggest the change of leadership has "worked" for the SNP in the sense that an unpopular leader has been replaced with someone who has better approval ratings than any other leading politician. But that apparent step forward isn't being replicated in the voting intention numbers. Quite the reverse, in fact. That's probably because, as we saw with Liz Truss (below), a party can still be tainted by the chaotic ending of an unpopular leadership even after the new management have moved in. 

The National: Ms Truss said the non-statutory guidance was insufficient (PA)

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What the SNP really needed was a good few months before an election was called in the hope that the public would move on, but they're not going to get that luxury.

The silver lining, though, is that John Swinney may still be enjoying some kind of personal honeymoon as the campaign unfolds. If this was a Holyrood campaign, I'd go so far as to suggest Swinney's greater popularity than Sarwar and Starmer might be enough in itself to turn things around for the SNP. In a Westminster campaign it's a different story, because no-one will even be thinking about whether Swinney would make a better national leader than Starmer.  Nevertheless, leadership may prove to be some sort of trump card for the SNP, and much will depend on whether they can negotiate fair representation in the TV leaders' debates.

The polling evidence is conflicting on whether there has been a boost in support for the Greens after their perceived ill-treatment at the hands of Humza Yousaf. The most positive signal was their 7% vote in the YouGov poll. If replicated on polling day, that would be a remarkable achievement, but it almost certainly wouldn't win them any seats, which must raise the question of whether some of those voters will end up looking elsewhere to achieve the maximum impact with their vote. 

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The National: Scottish Greens leaders Patrick  Harvie and Lorna Slater pictured in Holyrood

Given that an extra 7% for the SNP would be enough to wipe out most of Labour's lead, the SNP must be kicking themselves that they've chosen this precise moment to upset a lot of Green supporters. They'll perhaps hope to repair some of the damage with emphasis on climate change action.

Meanwhile, the Alba Party have anything between zero and 3% of the Westminster vote, if the polls are to be believed. Logic always suggested that they would focus all of their energies on the two seats they currently hold, with the realistic hope of securing creditable results given the relationship their sitting MPs have built up with the local electorates. Curiously, though, they've opted for the opposite strategy, and will be standing in a substantial proportion of Scotland's constituencies. This creates the danger that their resources will be spread too thin, and that they will end up with a very low vote in each seat they contest.

None of the pro-independence parties, then, have grounds to be bursting with confidence as they head into the campaign. But there has been a high number of totally unexpected election results over the last decade, and for that reason if for no other, it's fair to say there's all too play for.