We’ll never know if Nicola Sturgeon is among those who daily solicit the intervention of the Almighty, Scots being traditionally reticent regarding their religious habits, or if she rather chooses her moments to seek divine guidance. What is not in doubt is that last week’s events at Westminster were an answer to the prayers, not just of Scotland’s first minister but to the entire movement for Scottish independence. No nationalist could have designed this scenario better.

The sight of the SNP’s Westminster leader, Ian Blackford, marching his MPs out of the chamber following his expulsion by the Speaker, John Bercow, might have been the defining moment of the drama but was not of itself the independence gamechanger. Nor was it the Westminster annexation of 24 powers coming back from Brussels in areas devolved to Holyrood. Nor even was it the paltry 15 minutes of debate permitted for Scottish objections to the government’s EU withdrawal bill. Rather, it was the openly sneering and imperious attitude of the entire Westminster establishment wretchedly apparent in each of these.

No matter how unpalatable you may find the outcome of any political dispute, you can come to an accommodation with it if the process has been characterised by mutual respect. Last Tuesday, there was no respect at any level: none for the devolved settlement for which Scots – unionist and nationalist alike – had fought for decades and none for the Holyrood parliament that had previously voted overwhelmingly to withhold its consent for the withdrawal bill. Where there ought to have been respect there was only scorn laced with spite. In these moments, Westminster was shorn of its self-regarding status and came to resemble the braying dormitory of some public-school sixth form when it’s time to bully the poor boys in their midst once more.

In Westminster's, devolved government is just a sop to those fractious Jocks to delude them that they have some control

It was a dreadful look and it will come back to haunt the main perpetrators. In these moments, too, it became clear that devolved government means something entirely different when viewed through the Westminster lens. In their eyes, it is unimportant – a sop to delude those fractious Jocks into believing they have some measure of control over their own lives.

Until then, SNP resentment over the conduct of the UK government throughout the Brexit process as it pertained to Scotland had been easy to dismiss by unionists as mere nationalist grievance-chasing. Even though Scotland had voted by two to one to remain in the EU, this hadn’t delivered a sufficient boost to the numbers seeking independence. Thus, the Westminster government felt free to dismiss SNP Brexit concerns as a sideshow. In their final putdown last week, though, as the withdrawal bill was voted through, they simply couldn’t help themselves. No matter where you looked there was gleeful contempt. It was as if Scotland was being told: “This is what real power looks like and there’s nothing you can do about it.”

This was apparent in the attitude of Bercow, who mocked Blackford even as he was dismissing him from the chamber for an imagined infraction of the rules. The poison was provided by Ian Liddell-Grainger from the Tories’ Flashman wing, who shouted “suicide” when Blackford asked: “What options are available to us in this house?” And it was evident later when David Mundell, that most hopeless of Scottish secretaries, said: “Scotland is not a partner of the United Kingdom – Scotland is part of the United Kingdom.”

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In that one dismissive sentence, he exposed the biggest lie at the heart of the unionist campaign in the first referendum on Scottish independence: that Scotland was an equal and valued partner in the greatest political union on Earth. It was apparent, too, in a bizarre outburst from the English political journalist Tim Shipman, who 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.”

I visited that great city’s Moss Side neighbourhood four years ago and discovered that hostility to the Westminster elites was as deep-rooted there as it was in Scotland. And it was painfully evident on Scottish television two days later, when two former Better Together strategists vied with each other in outright condescension about the issue of consent at the heart of the SNP’s position.

The UK government has sought to portray the SNP’s anger over the power grab as illusory to the point of non-existent. “The 24 powers will eventually make their way to Holyrood, so what’s the problem?” they ask. The problem is threefold and they know it. It could take up to seven years for these powers to return, a period that would outlast a term of government on either side of the border. At any time, during this period the UK government could alter them as they see fit. A precedent has also been set allowing any UK government to override the Sewel convention by which Westminster won’t legislate on devolved competencies without Holyrood’s permission. The SNP has added more than 5,000 new members since the Westminster Awakening, while several prominent Better Together supporters have pledged support for independence.

The Tories and their Scottish Labour footstools had lulled themselves into believing that the union would always receive unconditional support from a majority of Scots. Last week, they learned there were conditions and that these were rooted in decency, mutual respect and honesty. A point exists at which your self-respect begins to erode if you continue to acquiesce in what has become a one-sided arrangement. I suspect for many that point was reached last Tuesday.

• Kevin McKenna is an Observer columnist