I GIVE the first word to the Member of Parliament for Dumfriesshire, Clydesdale and Tweeddale. Speaking in the House of Commons yesterday, David Mundell said: “Scotland is not a partner of the United Kingdom; Scotland is part of the United Kingdom.” Clunk, whirr, wallop. Partisan rhubarbing behind him, partisan rhubarbing in front of him – into the valley of death, rode the Secretary of State for Scotland.

Mundell may prosecute his arguments with all the grit of an anxious blobfish. His appearance before MPs yesterday was a characteristically huffy combination of self-justification and St Trinian’s scolding in the manner of Alastair Sim’s Miss Millicent Fritton. But on this occasion – in this brief passage – our havering Secretary of State was a model of clarity. Bravo, I say.

Because what David Mundell said has the chief merit of being true. It finally – mercifully – dispenses with the meretricious twaddle about the United Kingdom being a partnership of equals.

It was twaddle then and it is twaddle now. Scotland is not an equal partner in the United Kingdom. Scotland has never been an equal partner in the United Kingdom. Except insofar as hypocrisy occasionally obliges UK ministers to pretend otherwise, no serious political actor on the UK stage believes that equality is possible or even desirable.

And if you are prepared to take a walk in the scuffed brogues of a Westminster lobby correspondent, you can understand why. To quote Tim Shipman – one of the UK’s leading political journalists. He tweeted: “I’m not clear why Scotland should be regarded as more important than, say, Manchester ... it is the SNP who presume that it has some saintly status.”

Rankle as this perspective might, out of kilter as Shipman’s comparators are – if you’re an ambitious UK politician who fancies being a shadow-sub-under-minister for the department of light rail and brownfield sites – consider this. Why should you give a damn for five and a bit million souls when political triumph and disaster will be determined by the other 50 million? Why bother giving the SNP delegation a fair hearing?

The political logic follows pretty smartly.

When they see you as a sideshow, it is all too easy to treat you like clowns. The idea your arguments should be treated seriously is a joke in its own. Remember, the clown is funny because he doesn’t know he looks ridiculous. He takes himself seriously enough for both of you. And this, I’m afraid, is what the SNP delegation looks like from the Treasury benches.

Only this explains the Tories’ antics this week. Only this explains how Mrs May’s administration imagined it might get away with its cynical Brexit manoeuvres. The braying laughter, the interruptions, the suicide gags – all of it is eloquent testimony to the worldview of the deeply dysfunctional party governing this country.

The SNP benches seemed stung – even surprised – by this’s week developments. I’m surprised they’re surprised. But their human reaction is to their credit. Holyrood has deliberated. Parliament has voted. Consent for the EU Withdrawal Bill has been declined.

In 2016, Westminster took it upon itself to pass a Scotland Act which “enshrined in law” that at least some fucks ought – normally – to be given about the Scottish Parliament’s attitude.

In defence of this principle, SNP MPs turn up in Westminster. Agree or disagree with their analysis: they’re putting substantial arguments in the national Parliament, in what they perceive as the national interest. Human decency and political seriousness say that no serious state would try to govern or reform itself in this way. The Scotland Act decrees it is a decision of some moment. But in the bonobo politics of the House of Commons, a volley of faeces is all you get in return for this sober-mindedness.

Westminster doesn’t work for Scotland. In its bones, it can’t. Its attentions are – perhaps understandably – always fixed elsewhere. This week, the Tory Party just forgot to pretend otherwise.

But the roots of this are deeper. For a bit of perspective, I’ve been re-reading Tom Nairn’s The Break-Up of Britain. This seminal work in Scottish political theory is now 41 years old and has run to three editions, the first published in 1977.

The first chapter is entitled the Twilight of the British State. By any reckoning, it has been a long twilight since Nairn wrote the work, but many of the features he identified four decades ago remain eerily familiar to the contemporary observer of British politics.

Discussing the genesis of devolution in Britain in the 1970s, Nairn observed “there was no real belief in a new partnership of peoples” behind the push for devolution. Such a partnership, he said, “was never conceivable without the most radical reform of the centre itself”. Westminster and Whitehall. Giving power away, he argued, “meant examining, and changing, the basis of power itself: the constitution, the myth-source of sovereignty, and all that it depends upon. The whole British political system had to be altered. There has been no serious question of doing this, for the sake of the Scots, the Welsh and the Ulstermen.”

Four decades on, Nairn’s darts still find their targets. Play Labour’s episodic whack-a-mole version of federalism if you fancy some idle diversion. Hanker after another Britain which is, at best, only hypothetically possible. The patter of equal partnership was – and remains – an ideological facade. A grace note. A knowing nonsense. A piece of rhetoric, to be dropped like a hot brick as soon as convenience and self-interests dictate. David Mundell’s distinction is to be the first to send it clattering.

The Tory Party is drunk on the idea of Westminster sovereignty. It is drunker than it has been in decades. As Nairn appreciated so clearly in the 1970s – and as we saw this week – the British State still remains “unable to contemplate radical reform of the centre, since its whole modern history has been built on avoiding it”.

Unbelievably, four decades on, two decades into devolution, the avoidance continues. For those of you exhausted and dismayed by this – made angry and sad – there’s only one solution.