Whatever other quality Gordon Brown may be said to lack, it is not consistency. His announcement this week of a new thinktank to help sustain the UK union is the latest initiative from one of the most vocal supporters of a no vote in 2014. At regular intervals he pops up to extol the virtues of being and staying British.

It’s a clarion call to support the continuation of the four-nation state that has found echoes in Boris Johnson’s pledge to be a “minister for the union” as well as a prime minister, and the former Tory leadership hopeful Rory Stewart’s earnest plea that a post be created to oversee the business of all the devolved administrations.

These very disparate political operators are united in their belief that the UK union is under serious threat from the double whammy of Brexit and nationalism.

Brown’s new wheeze is Scottish Future, headed up by Prof Jim Gallagher, an erstwhile civil servant and long-time Brown ally who serves on the board of the campaign group Scotland in Union, and was one of the go-to no pundits during the last independence referendum. Its first outing next month will be devoted to scrutinising the various proposals for a new currency, should Scotland become a separate state. It is Brown’s contention that the full cost of independence has not been addressed.

It would be idle to pretend that supporters of Scottish independence speak with one voice on fiscal issues – which was arguably a decisive factor in the 2014 referendum. The growth commission set up by the Scottish government set out a softly-softly approach to new currency arrangements, involving a series of tests that had to be met before sterling could be replaced by a Scottish pound. That plan failed to enthuse delegates at last year’s Scottish National party conference, with whom the first minister, Nicola Sturgeon’s safety-first, ultra-cautious approach is wearing thin. Members voted for a move to a Scottish pound “as soon as was practicable”.

Facebook Twitter Pinterest ‘Among Scots there has been widespread disgust at the proposal, post-Brexit, to take back powers from Brussels directly to Westminster.’ The chamber of the Scottish parliament in Edinburgh. Photograph: Ken Jack/Corbis via Getty Images

But the point is that the most fervent debate in Scottish political circles is no longer about independence versus the status quo. Brown’s latest plea for Britain may well be accompanied by the loud sound of stable doors shutting long after the horses have sought fresh pastures. The Labour party in Scotland is on life support under the less-than-charismatic leadership of Richard Leonard. Ruth Davidson’s 13 Tory MPs – three more, let it be remembered, than the Democratic Unionist party can muster – were split over supporting or opposing a Johnson premiership. (Some set up Operation Arse to try to stop Johnson. That went well.)

Meanwhile, among independence-supporting voters in and out of the SNP, the debate is raging over whether the Scottish government should continue to bide its time hoping that a new, post-Brexit administration will order another legal referendum, or whether it should go for broke and declare the next Scottish election in effect a vote on independence.

The problems for those trying to stem these tides are many and varied. Scotland, where in 2016 a majority voted to remain in each of its 32 regions, wants to stay in Europe and its government has been accelerating contacts with the European commission.

Johnson, the likely new prime minister, has achieved the remarkable feat of being less popular in Scotland than Nigel Farage. One poll last month found that his premiership would result in an increase in the pro-independence vote to 53%, eight points higher than in 2014.

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There has also been a failure to involve the devolved administrations in the Brexit process, and a palpable disdain for the joint ministerial council representing Scottish, Welsh and Northern Irish interests.

And among Scots there is widespread disgust at the proposal, post-Brexit, to take back powers – even those that had previously been devolved – from Brussels directly to Westminster. Not so much more devolution but entrenched centralisation.

David Mundell, the hapless secretary of state for Scotland – surely the most redundant of jobs in the modern political era – has just been celebrating getting the keys of a new government hub in Edinburgh with space for 3,000 civil servants, and a cabinet room. His problem is that there is an existing political hub in the Scottish capital. It is called the Holyrood parliament and it has just celebrated its 20th birthday. Admittedly, the UK cabinet is unlikely to be invited to sit there.

• Ruth Wishart is a Scottish columnist and broadcaster