Everything the SNP once stood for is being shredded at the Covid Inquiry. The very clothes it wore are in tatters. The garb of honesty and integrity is ripped ragged.

There’s something of Macbeth’s last stand about it all. At play’s end, Shakespeare says of the once-loved king, brought low by hubris and connivance, that the royal gown “hangs loose about him, like a giant’s robe upon a dwarfish thief”.

The SNP is all but naked. For those who once bought the promises, the emperor is shameful to look upon now the fairytale-spell has broken.

Clearly, battalions of true believers remain. Loyalists to the last bitter hill, they refuse to countenance any change in fortunes. "All’s well," they shout, as disaster rains down. For them, every fresh proof is just "fake news".

Neil Mackay: SNP may be finished but independence is worth fighting for

Eventually, all political parties, as voters leave and power ebbs, collapse into a black hole of cultishness, maintained solely by those with nothing left but blind allegiance.

We saw it with Tony Blair, and Margaret Thatcher. We see it across the world, in every democracy. This is how power ends: entropy and defeat. It’s a common political tale.

Yet it’s still a sorrowful spectacle to watch: folk who should know better defending the indefensible, denying the evidence of their own eyes.

The one truth SNP loyalists will never accept is that thousands of moderate independence supporters are done with their party, and increasingly drifting towards Labour.

You’ll still hear cries of "But nobody would vote Red Tory!" as the good ship SNP sinks below electoral waves.

I reckon I’m just the voter whom the SNP fears losing, and Scottish Labour must win. My voting history dovetails with many. I’m an old-fashioned social democrat.

I vote for the party I believe will work hardest to achieve the fairest society. Limit the inequities of the free market, address the damage it causes, and my vote is yours.

So, clearly, for most of my life, I’ve voted Labour. Was Blair a social democrat? No. Was he my best hope? Yes. Was I failed? Yes. Repeatedly. And Blair’s monstrous invasion of Iraq was the final straw.

In 2003, I was done with Labour, left politically homeless for years. I detest nationalism so the SNP wasn’t even on my political radar.

Then, though, after the SNP’s first government term, I started to think somewhat differently. I liked its commitment to maintaining the abolition of tuition fees. Though it should be pointed out that Labour first abolished up-front fees in Scotland. Nevertheless, free university education became key to the SNP’s appeal.

Neil Mackay: The SNP is a deflating balloon, its future is bleak

I welcomed the scrapping of prescription charges. Free personal care for the elderly - although far from a perfect policy, and in need of much improvement - also became an SNP pledge. Though, again, this was pioneered by the Labour-LibDem coalition.

However, with Labour anathema to many left-of-centre voters post-Iraq, the SNP’s commitment to maintaining these egalitarian - or at least partially egalitarian - policies was attractive.

Later, I liked the principles behind policies like the Baby Box. Despite holding no torch for nationalism, I had - theoretically - never opposed Scottish independence. I support Irish unity, so why shouldn’t Scotland have the same rights?

I’d also concluded that Westminster was frankly irredeemable. The political system couldn’t be fixed to the benefit of the people. So it wasn’t hard for me - once the SNP projected the notion of "civic nationalism" - to incline towards voting Yes. After 2014 - like a vast swathe of Scotland - I lent the SNP my support.

Will I in future? I don’t know. Will I vote Labour? I don’t know. For social democrats, there’s little to admire in Keir Starmer. Yet I want an end to this disgraceful Conservative Government. So Labour lures me. Meanwhile, my trust in the SNP has evaporated. This, I believe, is a common story for many Scottish voters.

Yet we moderate independence supporters, who just might vote Labour, will cause agonies for Anas Sarwar and Starmer. Labour now has its greatest lead over the SNP in a decade. It’s on 36%, and the SNP on 33%.

The Herald: Where will indy voters go after the Salmond-Sturgeon era?Where will indy voters go after the Salmond-Sturgeon era? (Image: Newsquest)

At a General Election, that converts to the SNP getting just 18 MPs, and Labour 28. Any hope the SNP had of using the national vote to push for a referendum is shattered, for now at least.

Yet support for independence remains unchanged since 2014, in fact, in some polls it rises above 50%. The days of independence being umbilically linked to the SNP are over. The child has left the parent. We’re in the moment of decoupling.

That’s a historic shift politically, leaving power wide open.

So how will Labour manage indy-moderate voters should we lend our support? Will it ignore our constitutional beliefs?

Starmer will inevitably disappoint social democrats with his milquetoast policies packaged for the Tory press.

How much more disappointed will pro-indy social democrats feel after a few years of Labour rule, unless there’s seismic constitutional change, amounting to, at least, a federal Britain?

Failure will see all those moderate independence voters leave Labour. History will repeat.

Yet appeasing indy-moderates will alienate Labour unionists. Result? Political nightmare and intractable double-bind. Whatever the SNP’s failures, it has changed the shape of Scottish politics forever.

Neil Mackay: Labour juggernaut will flatten SNP and may flatten indy too

Starmer will be in power for two terms, at best. Conservatives will return. By then, if the SNP hasn’t been replaced by a better political vehicle for independence - most certainly not Alba - then Nicola Sturgeon and this current administration’s failures will be distant memories.

Independence won’t happen anytime soon. But in a decade from now, maybe less, when the Yes movement has swapped the suit of clothes it wore, with a tattered tailor’s label bearing the imprimatur "Salmond & Sturgeon", for a better outfit, then we’ll find the wheel of fortune turning again. Labour will lose, the Tories will win, and a party of independence will be back.

Certainly, independence supporters won’t abandon their beliefs simply because the SNP is defeated. That’s not how belief works. Did Scottish unionists give up their beliefs because Labour and Conservatives were defeated in Scotland?

Any unionist who thinks independence will evaporate along with SNP votes is as deluded as those nationalist hardliners who today cannot see electoral ruin coming straight at them.