OUT and about in Glasgow’s Buchanan Street on Saturday it was hard to miss the Christian chap with the megaphone next to the statue of Donald Dewar, shouting the usual stuff about sinners going to hell. I don’t doubt he believed every word. But it was all so cliched and embarrassing folk simply turned away and walked on.

As I read Gordon Brown’s latest dire warnings about the dissolution of the UK, which included an assertion that the country is “sleepwalking to oblivion”, I kept thinking of the megaphone man. After all, that’s what the former Prime Minister has turned into: a street corner preacher with a sermon nobody wants to hear.

That’s not to say Mr Brown is wrong. His prediction that a no-deal Brexit will lead to Scottish independence looks more accurate by the day, while his claim that the “comfortably unifying Britishness” of the post-war settlement has been swept away is also entirely right. It's the underlying slur in these regular dispatches that immediately turns folk off, the insult to the intelligence of Scots, and indeed everyone else in the UK, in the way he equates the “toxic nationalism” of Boris Johnson’s no-deal crusade with Scotland's right to choose a different future.

Read more: UK is 'sleepwalking into oblivion', says Gordon Brown

At first glance this knowing and very deliberate conflation of the two, that spitting of the word “nationalism”, purports to be about the sort of internationalist socialist ideals that kept the Labour vote united throughout much of the 20th century, the "commonality of workers in Glasgow, Sheffield or Cardiff" line that undoubtedly stopped some voting Yes in 2014.

Leading Labour MP Stella Creasy was at it too last week, after Jeremy Corbyn's deputy, John McDonnell, blew Scottish Labour’s policy of unequivocal opposition to indyref2 out of the water by saying it would be for the people of Scotland to decide whether another referendum should be held. “Nationalism is the antithesis of socialism,” she pronounced haughtily on Twitter. “To prioritise passports over principles isn’t progressive. Egalitarian devolution isn’t about separation but how by working together as nations within the UK, each stronger and more successful. Labour abandons such commitment at our peril.”

Beneath the surface of this caring, sharing egalitarianism is a clear and concerted bid to make Scots feel bad and dirty about supporting self-determination. After all, independence remains an inconvenient and irritating prospect for a Labour party that has been consumed by chaos on both sides of the border.

Read more: UK is 'sleepwalking into oblivion', says Gordon Brown

But the severity and fluidity of recent events mean the party’s automatic refusal to countenance even the notion that independence is a legitimate position, is crumbling. And those who cling on to it are being roundly and rightly called out or, as in the case of Mr Brown, simply ignored.

Let’s me be clear. It’s perfectly acceptable for defenders of the union to say they are opposed to independence and would campaign against it in any future referendum. But to repeatedly suggest that self-determination is in itself some sort of evil, some sort of betrayal, is not only wrong, but insulting and hypocritical.

In Mr Brown and Ms Creasy’s world independence sympathisers (more than half the Scottish population if the latest polls are to be believed) are… what exactly? Selfish? Stupid? Misguided? Guilty of some sort of thought crime?

Of course, the pair are not just talking rot, but the sort of dangerous rot that – as their own predictions about the disastrous ramifications of No-deal Brexit outline – would have Scots knowingly harm their own economic, social and intellectual interests in order to keep afloat dying notions and entities that are no longer fit for purpose. For many Scots continuing to administer these self-inflicted wounds will not only seem problematic, but out and out madness. That's why it would be perfectly sensible and legitimate to have the opportunity to choose another course.

Indeed, all this is particularly galling because over the last three years Labour has done hee-haw to defend any of the folk it purports to represent from the catastrophe of Brexit, throwing them instead to the right-wing Tory wolves who are devouring the last remnants of the union and will think nothing of consuming livelihoods and communities in the name of no-deal. As another recent poll highlighted, the Tory membership that voted for Boris Johnson as PM would happily sacrifice both the economy and the union to achieve Brexit.

Whether or not Parliament can or will stop no-deal remains unclear. But you can tell how precarious the union is by the number of Labour and Lib Dem MPs talking up the fantasy of federalism again. It would be genuinely funny if it wasn’t so very grim.

Mr McDonnell’s recent change of tune may be first and foremost about the need for SNP support for any future Labour government. But it at least recognises the fact that many of his party’s voters support not only indyref2, but a Yes vote.

Importantly, it also accepts that Scottish independence is a legitimate position, even if one does not support it. Until Mr Brown follows suit he will not only be insulting his compatriots, but screaming into the void.