BRITAIN is revolting. The sight of Nicola Sturgeon denouncing Theresa May and all her works at a press conference yesterday may be familiar enough, but Scotland’s separatists increasingly find themselves just one grumpy part of a UK-wide coalition that likes nothing better than applying its boot to Westminster’s posterior. With Parliament looking more dysfunctional by the day, power is draining from the centre to the peripheries in ways that are radically changing the way our country is governed.

It’s happening almost by accident. The advent of high-profile, directly-elected mayors in England’s regions has created a fixed focal point for debates about local wants and needs, acts as an assertion and stimulant of that nation’s many discrete, deeply-felt identities, and provides a super-accountable and modern form of politics that contrasts starkly with the fusty oddness and distant yelping of Westminster and its many glory-lusters. This has coincided with a weak Tory minority government and a fruitcake Opposition more interested in socialist sloganising than winning elections.

The powers that have flowed along these newly-opened tributaries to England’s great cities and regions – to Andy Street in Birmingham, Steve Rotherham in Liverpool, Andy Burnham in Manchester, Ben Houchen in the Tees Valley, Marvin Rees in Bristol, Sadiq Khan and his predecessors in London, and others – will only intensify. As Donald Dewar once put it, devolution is a process rather than an event. Mr Rotherham has already echoed this sentiment, saying that the deal which created his post is a “journey and not a destination’” New bureaucracies are like flypaper, stickily gathering heft as time passes.

Brexit is the first big test of this fresh settlement. It has arrived just as the debutant mayors have settled behind their desks and begun to try out the levers available to them. They are substantial figures in their own right, some locally, some nationally, with ambitious plans and a bully pulpit. Mr Burnham didn’t walk away from Westminster for a quiet backwater existence. Nor did Mr Khan or Mr Rotherham. Mr Street ran John Lewis, one of the country’s most respected brands, for the best part of a decade. Why languish in opposition or sit dozing on the backbenches when you can be a muscular local hero who actually gets stuff done? Formidable individuals with a democratic mandate, strong opinions and a willingness to fight for their electors – it’s not rocket science to figure out where it’s all going. Especially if you’re Scottish.

Ms Sturgeon yesterday published a withering assessment of what Brexit could mean for Scotland’s economy. Mr Khan has commissioned a similar study for London, which is due later this month. Both were inspired by the failure of the UK Government to produce credible impact assessments of its own. “It is outrageous that the Government either failed to properly consider the impact of Brexit on Britain’s economy, or is refusing to release its analysis. We need to know the impact of different scenarios on our economy in order to deliver a Brexit deal that protects jobs and growth,” the Mayor of London said. Yesterday, Ms Sturgeon struck a similar tone: “The fact that the Prime Minister wants to leave not only the political structures of the EU but come out of the European Economic Area shows just how extreme the UK Government position is.” She represents a nation in which 62 per cent backed Remain; Mr Khan’s London was 60 per cent Remain. Those decisive majorities provide considerable moral authority.

A further sign of how the political playbook is being rewritten came recently when Mrs May proposed letting Northern Ireland maintain close links to the EU (and therefore the Irish Republic) after Brexit, to avoid upsetting the Peace process. It didn’t go well, and it wasn’t just the DUP that predictably rebelled, over what it saw as a threat to the Union. Ms Sturgeon demanded equal treatment for Scotland. Ruth Davidson insisted the final Brexit deal should be applied uniformly across Britain. Carwyn Jones, the First Minister of Wales, wanted the same as Ms Sturgeon. Then the mayors waded in. Mr Khan wanted special single-market access for London. Mr Rotherham argued that Liverpool and Manchester should also be given a “differential” settlement: “If you think about Liverpool City Region and Manchester City Region and our functional economic geography, we have a bigger population GDP-GVA than Scotland.”

The SNP has been grumbling for some time about a possible Westminster “power grab” when matters currently decided at an EU level are returned to the UK, especially in areas such as farming and fishing. The regional mayors have now taken up the case. Mr Rotherham, Mr Burnham and Mr Houchen have written to David Davis about post-Brexit funding and the need for repatriated powers to be devolved.

This, then, is the beginning of something. With Westminster repeatedly proving itself lacklustre or toothless when it comes to tackling important issues such as, say, housing and homelessness, a clever local politician could step up and show the way. These new offices may turn out to be a fruitful training ground for future national leaders, providing useful experience of governing and an understanding of the country and its priorities outwith the Westminster bubble.

Typically, Ms Davidson, whose political antennae are as good as they come, has picked up on these intriguing possibilities. By chance, she bumped into Mr Burnham at a filming of Strictly Come Dancing in Blackpool late last year and the two agreed they were lucky to be absent from Westminster during the difficult Brexit era, able to focus instead on other, more immediate and rewarding policy areas.

As she looks to the 2021 election, Ms Davidson is studying closely how Boris Johnson operated during his tenure as a Tory Mayor of London with another Tory in No 10. Mr Johnson picked his moments to publicly disagree with David Cameron and George Osborne on key issues in order to endear himself to his liberal London electorate. Ms Davidson will similarly seek to differentiate the Scottish Tories from their colleagues at Westminster ahead of the election. She wants to show she can extract generous deals for Scotland from Whitehall, too. “If there are portions of pork, she wants her slice,” a source tells me.

We’ll have to get used to the tail violently wagging the dog. Looking at the sorry state of affairs in Westminster, I’d say that’s a good thing.