One of the more confusing dynamics of the British constitutional struggle, for those paying only intermittent attention to it, is the way that separatist parties can make huge electoral gains without advancing their core objectives much at all.

The Scottish National Party is the most obvious example here. Winning an overall majority in Holyrood in 2011 was an impressive achievement, but it was only in the wake of its defeat in the independence referendum in 2014 that it managed to consolidate the Yes vote to become the hegemonic political power it is today.

There are no hard trade-offs, no disappointments

Sinn Fein has achieved no such breakthrough, despite what some excitable mainland commentators seem to believe. But it has become the largest party at Stormont by a similar means: consolidating a minority nationalist vote whilst the rest of the electorate fractures.

To some, the sight of two separatist leaders “in power” over devolved governments must surely auger the break-up of the United Kingdom (even if Sinn Fein’s position has not actually changed, except relative to the ailing Democratic Unionists).

But whilst it is obviously not good for this country’s long-term health, one can also make the opposite case: that both parties are profiting electorally from the fact that their respective ambitions for Scotland and Northern Ireland are so far from being achieved.

Neither party has a proper, fleshed-out plan for what independence or union with the Republic would look like. That means that each can be whatever its supporters want it to be. There are no hard trade-offs, no disappointments, no uncomfortable truths to confront.

In Scotland’s case, that means that independence can (at least in the heads of its supporters) mean much higher levels of public spending without huge tax increases, despite the fact that independence could cut the country off from British fiscal transfers of which it is a substantial net beneficiary.

Meanwhile Sinn Fein have an even trickier job: upon annexing Northern Ireland, Dublin needs somehow to maintain Northern Irish public service levels — paying to see your doctor would not be a winning proposition in a border poll — without having to place the burden of paying for it on the Republic’s much smaller base of taxpayers.

It also needs to convince wavering unionists that the result would be a new Irish state which reflects their different history and values. This without spooking voters in the South, who support unity in theory but are very attached to the symbols and institutions of their country and show no sign of being prepared to change the flag, anthem, constitution or anything else in order.

Both sides attempt to wish the problems out of existence. Sinn Fein’s intellectual outriders pretend that joining the Republic would magically revitalise the Northern Irish economy and that the United Kingdom would assume ongoing liability for things such as public sector pensions (it would not). The hallmark of a really dedicated Scottish nationalist is the belief that the Scottish Government’s own statistics, which show that the country gets more out of the Union than it pays in, are fake.

Happily, this sort of fantasy politics is not enough to build a majority coalition for either proposition. The SNP has not made any progress on persuading a larger share of Scots to support independence since 2014, despite the shrill insistence of pro-Remain campaigners that Brexit would turbo-charge their cause. Polls in Ulster show that there is nothing like a majority of voters in favour of severing its links with Britain.

Brexit represents a big call of nationalist bluffs

This would not, on its own, have been enough to prevent both parties doing further damage to the United Kingdom. But whatever its other failings, we have been extremely fortunate over the past five years to have a Government which refuses to throw red meat to these paper tigers.

Under the “Millennial consensus” ushered in by New Labour, the response to any success by a national party was to make more constitutional concessions. This process weakened the UK. Bizarrely, the failure of the devolutionary strategy allowed its advocates to claim the danger was mounting and double down on it, leaving the UK weaker and weaker still.

Brexit, and the years after it, represents amongst other things a big call of some big nationalist bluffs. Remainers insisted a vote to leave the EU would break up the UK, yet in Wales and Scotland the separatist cause has not advanced an inch. Such damage as the Protocol has done in Northern Ireland was self-inflicted by hapless London politicians who were gulled into accepting that the Belfast Agreement stipulates an invisible border with the Republic (it does not).

Subsequently, the devocrats insisted that the electorate would not suffer the attack on their privileges represented by the UK Internal Market Act. Yet the legislation landed with no great popular backlash. Voters are simply not nearly as invested in the prerogatives of their local rulers as those rulers would have London believe.

The United Kingdom is not on some inevitable track to disintegration. The real threat remains, as it has for a long time, not the separatist parties formally arrayed against it but the dire performance of the unionists theoretically committed to defending it.

In Northern Ireland, the Unionist parties have completely failed to adapt to the post-Belfast Agreement reality that the Province’s constitutional status doesn’t hinge on election results. Their shrivelled “keep-the-shinners-out” offer has alienated a big section of the electorate which just six years ago returned 55 Unionist MLAs versus 40 Nationalist ones.

On the mainland, Labour’s tendency towards intellectual ancestor worship means that Sir Keir Starmer has endorsed some vague plan from Gordon Brown for “radical federalism”, a programme which will do much more to usher in the end of the United Kingdom than a record local election result for the SNP.