“The UK is becoming a failed state, focused on enriching a Tory elite and impoverishing the rest.” Not the words of an excitable Momentum agitator or a red-faced ranter in the Question Time audience, but of a Scottish Cabinet minister.

Mike Russell, Nicola Sturgeon’s Brexit secretary, was tweeting angrily in response to a report on UK poverty by UN Special Rapporteur Philip Alston. Austerity, said Alston, had been “punitive, mean-spirited and callous”. “For almost one in every two children to be poor in twenty-first century Britain is not just a disgrace, but a social calamity and an economic disaster, all rolled into one.”

Russell’s rage mirrors a sudden burst of furious rhetoric across the pro-independence movement. The calamity being made of Brexit, and the sense that the SNP government is largely being ignored by Theresa May and her ministers, is driving calls for a second indyref to be held sooner rather than later. This was not in the plan. In her conference speech last month, Sturgeon asked for “pragmatism, perseverance and patience” from her supporters, warning that “our task now is to step up our work to update and strengthen the case.”

It looks like that restraint will not be forthcoming. This week Patrick Harvie, leader of the Scottish Greens, whose votes the minority SNP administration relies on to pass its legislation, said there was now enough clarity around Brexit for Scotland to vote again on independence. Mhairi Black, the young and influential SNP MP, said that if the Westminster government collapses and a general election is called “then it’s time for the SNP to put independence at the core of the manifesto.”

Sturgeon’s cautious approach to a rerun is irritating some. Tony Banks, a wealthy businessman and SNP donor who helped fund the 2014 Yes campaign, accused the First Minister of “getting to be as wishy-washy as Maybot!” Writing on Facebook, he said: “The democracy we live in does not respect the will of the people of Scotland. Civil disobedience, UDI [unilateral declaration of independence], another Scottish referendum — what lies ahead? Time for the Scottish politicians to stand up for Scotland. If the SNP cannot get Scotland on an immediate road to leaving the UK then Nicola Sturgeon needs to go.” Others in the movement have called for a return to the old SNP policy that winning a straight majority of Scottish seats at Westminster would be a mandate for independence.

The danger in all this is twofold. First, the SNP leadership will be nervous about losing control of the narrative around a second referendum. Although Sturgeon’s position is under no immediate threat, there is concerned chatter about who succeeds her and when, and about the broader direction and strategy of the independence movement. There is also frustration at the extraordinarily tight grip the First Minister and her small team of advisers keep on policy and tactics.

Second, while the First Minister believes Brexit may well persuade a majority of Scots that the UK is a busted flush and that their future lies in a new independent state, she is also aware that most want to see how the next few years play out. Brexit is risk enough – the argument that breaking up Britain is a logical and sensible next step is far from won. It may be that the events of the next few months lead to a sudden shift in public opinion in favour of another indyref, but at present that seems unlikely. Support for independence has barely shifted from the 45 per cent it attracted in 2014.

More likely, perhaps, is that the grim events playing out in London continue to gradually fray the bonds that bind Scotland to the Union. Independence may not yet have majority support, but for many unaligned voters it is far from the unthinkable prospect it once was. The political conversation in Scotland is almost entirely detached from the one taking place at Westminster. The longer-term consequences of this drift would seem to be in the SNP’s favour.

Sturgeon knows all this and, like her fellow members of the SNP old guard, sees the value in playing the long game. It is, after all, what got the SNP to its current position of unchallenged predominance. But the question is whether she can contain the anger being unleashed by Brexit across her movement. How does she harness and maintain that energy while avoiding a reckless headlong rush to a second indyref that would almost certainly lead to another defeat and set back the cause by decades? How does she maintain her control of the movement without bending to its will?

There had been hope that the next few years, as we prepare for the 2021 devolved election, would see a national debate on the most pressing domestic policy issues – our wholly unreformed education system, our creaking health service, our underperforming economy. It seems, though, that the Yessers are determined Scotland will continue to talk about nothing but independence.