The Financial Times sums it up rather nicely: “For Scottish Nationalists, the timing is painful”. It refers to the latest ‘Government Expenditure and Revenue Scotland’ (GERS) figures, which reveal that, as the Spectator puts it, “an independent Scotland would now be bankrupt”.

Compared to the panglossian predictions of the SNP’s pre-referendum ‘White Paper’, the collapse in oil revenues is close to total. To quote the Speccie again: “In the SNP’s economic manifesto for independence, it gave estimates of up to £7.9 billion a year for oil revenues. Then the oil price crashed – and oil revenues are now 99 per cent lower, at £60 million.”

It doesn’t really need reiterating again how bad this is for the economic prospectus for independence. Suffice to say that it leaves Scotland with a wholly unsustainable deficit which would force any independent Scottish Government to make some eye-wateringly painful choices about tax and spending.

But for all the recent talk about being open about the ‘downsides’ of independence, acknowledging the scale of the “challenge” would be lethal to its prospects. Scots didn’t vote Yes when it held out the prospect, however illusory, of greater prosperity. The certainty of hardship will only shift the dial the other way.

Why need this be a problem? After all, the vote was only in 2014. Couldn’t the SNP have waited, using their period in government at Holyrood to try to create the sort of dynamic on-shore economy that would end their dependence on oil statistics?

Perhaps, but the great strategic weakness of the Scottish Nationalists is that they have relatively little room to manoeuvre. The clever ones – and that definitely includes the party’s leadership – recognise that the broad coalition delivering their thumping election victories is almost certainly too incoherent to stick together long term.

Talking up independence, and all the amazing things that can be done after independence, has allowed the SNP to win the loyalty of working class, urban voters who are abandoning Labour despite the fact that it governs as a centrist party of the middle class.

But talking up independence alienates another chunk of the Nationalist vote: well-off, rural voters in places like the North East (which voted heavily for ‘No’ despite being an SNP heartland), who developed the habit of voting Nat because they provided a better bulwark than the anaemic Tories against Labour – the party whose clothes the Nationalists have stolen.

So talking down independence and focusing on governing invites, due to the new powers Holyrood is getting, the certainty of taking decisions that have losers. That will decrease SNP support.

But talking up independence risks alienating those voters who back the SNP despite, and not because of, their position on Britain. This is especially so with a revitalised Scottish Conservative Party as an alternative – and we’re already seeing the effects, as this seat analysis illustrates.

Time is not on Nicola Sturgeon’s side. To be sure of another referendum the Nationalists need to be able to call one whilst they still have the working-class ‘Yes’ votes needed to win it and the ‘Tartan Tory’ electoral support to be in power to call it.

They are also under pressure to make the break, if they can, before post-Brexit Britain becomes the new normal. But if they lose a second time, as Quebec shows, they lose for decades.

Personally, I’m inclined to believe the SNP when they said that Brexit was not their preferred “trigger”. Rather I think they have been trapped: believing Brexit wouldn’t happen, they could afford to put it in the manifesto as a bit of red meat for the faithful. Then it happened.

Despite her bullishness the morning after the vote, the First Minister has since been rowing back on the likelihood of another vote. Theresa May deserves a great deal of credit for the pains she has taken to be respectful to Scottish interests, but this is also because (as predicted on this site), the oft-predicted surge in separatist sentiment Brexit was meant to unleash has not materialised.

There was never all that much of a reason to think it would. Scotland is like the rest of the UK, only more so, in having a political class that is disproportionately well-disposed towards the EU. The four-in-ten Scots who voted Leave don’t have their views reflected in the policies of any Holyrood party or more than a handful of MSPs.

Pro-Remain Scottish commentators and politicians painted a portrait of Scotland which didn’t really match up to the available evidence, which suggested that Scots were substantially more Eurosceptic than their governing class and that independence swing voters in particular were a deeply risk-averse, financially-minded bunch.

That’s why these GERS figures make the SNP’s dilemma so acute: they damage it with the swing voters it actually needs to win a second independence vote, who are not outraged Europhiles but cost-conscious neutrals. If they wait too long they might not get a second vote at all. But if they lose it, they lose big.