First, a word of warning. What I’m about to say is based on opinion polls and the percentages in the opinion polls are unlikely to be exactly what pans out when there’s a general election and the probability of me being wrong about that is 75.34% or thereabouts, possibly, maybe. You get my point.

But now that I’ve made the point, allow me to gawp for a minute. If the polls are correct, SNP support is down about 10% on a year ago and if it doesn’t go up again, the SNP would lose some 23 seats to Labour, including six of its seven Glasgow constituencies. I’m not surprised really that some excitable Labour people are talking about Clydeside turning red again.

However, this is not the easiest thing to pick apart, for a couple of reasons. Firstly, support for the SNP is still remarkably high given what’s been happening in the last few months (I mean, come on, what will it take for some people?) Secondly, support for Yes also seems pretty solid, which in a way is a healthy thing: perhaps we’re (finally) starting to realise independence is not the SNP and SNP is not independence.

It's that second factor I think – support for independence – that has been mainly buttressing support for the SNP for a long time now, but it’s not the only one, particularly in Glasgow and Dundee. It’s no coincidence that the two cities with the highest levels of deprivation have also had the highest levels of support for independence. Many Yes voters were hopeful that independence might create a different Scotland and improve their lives, and who can blame them really?

But the fact that independence is now a long-term rather than a short-term prospect, combined with the fact that the pressures on families living in poverty have increased significantly in the last year or so, means many people are now starting to look at options other than independence. And the most obvious one – perhaps the only one – is Labour. Perhaps it’s this more than anything else that explains why the SNP is losing Glasgow.

There are other factors of course, including the personal one. Nicola Sturgeon was a west-coaster with strong links to Glasgow. She was also popular in the city; indeed, I voted for her myself when I lived on the south side (who was I then I wonder?) My point is that Humza Yousaf, who now lives in Dundee, doesn’t have the same personal local factor to play on. Glasgow loves people who love Glasgow but it particularly loves people who stay put.

There’s something else as well that isn’t really working any more for the SNP – in Glasgow but in other places too – and that’s Brexit. At this point, I should probably issue a trigger warning: I am about to quote Alyn Smith. The nationalist MP said the other day that the “total mess” of Brexit demonstrated the cost of Westminster politics. But this is starting to feel like the ghost of arguments past isn’t it? Brits, Scots, us, we’ve kind of moved on.

In a smaller way, you can detect the same sort of thing starting to happen with independence, even in Glasgow. There was a time, not so long ago, when independence cropped up in almost every conversation round the dinner table, or in the pub, or in the office, and if it didn’t it was because people were tiptoeing round it, but that’s not the case now. I’m struck by how infrequently it comes up these days with the people I meet day-to-day in Glasgow and that may also be because we’ve kind of moved on (for now).

Some of these factors are not unique to Glasgow obviously, but they intersect in the city in a way that has benefited the SNP for the last ten years or so but is now working against them. It’s also worth remembering that this kind of thing – change of personnel, change in circumstances, a change of luck – happens to all parties and most of them recover in time; politics is a circle, not a straight line.

Even so, Glasgow undoubtedly remains a particularly tricky issue for the SNP. Remember: Glaswegians have been here before – apparently being taken for granted by the ruling party and they don’t like it much. Falling support in one of the citadels of Yes also raises a serious existential question for the party. If the support of Glasgow was central to the SNP’s dominance of the independence movement, what on Earth will replace it?