Amidst all the dry economic arguments, one of the more emotive fronts on which the 2016 referendum was fought was whether Brexit could lead to the dissolution of the Union. Some Remainers made the argument that dragging Scotland, Wales, and Northern Ireland out ‘against their will’ would turbocharge support for independence. Unionists such as myself – who ended up on the Leave side – saw it differently: EU membership was actually making it easier for the SNP to sell separation as a low-risk proposition. Shared membership of the EU would, after all, allow Scotland as a newly-independent country to enjoy relatively normal social and economic relations with England.

While the SNP did its best to weaponise Brexit in the aftermath of the referendum, in the end it failed to yield the sort of surge that some, including Nicola Sturgeon, were evidently expecting. It took the advent of the Covid-19 pandemic, and the Government’s mishandling of it, to push support for independence to the levels we were supposed to attribute to Brexit.

But that doesn’t make it unimportant. Leaving the EU has alienated a section of liberal voters who backed ‘no’ in 2014, whose attachment to Britain is at least much more conditional than it was. This was, for a time, compensated in part by the defection of pro-Brexit voters from the SNP, although Alex Salmond’s contribution to the cause may yet be wooing these back with his Alba party.

Yet it is also true that Brexit, and especially the harder form of Brexit secured by the Government, makes life more difficult for the separatists, precisely by taking away the easy sell of ‘the best of both worlds’. A new report from the Institute for Government looks in detail about what an independent Scotland joining the EU would mean for the ‘Anglo-Scottish border’.

As one might expect, the economic portrait it paints isn’t pretty. The rest of the UK is a much more important export market to Scottish businesses than the EU. Scotland would also go from being a net recipient of fiscal transfers inside the UK to likely being a net contributor in Brussels, as it would be unlikely to secure the rebate Britain enjoyed. It would also probably have to commit to joining the euro, at least in principle.

But we know from 2016 that such narrow economic considerations are not always as powerful with voters as strategists might hope. Which is why I think two other takeaways from the report are probably more important.

The first, as summarised by one of the authors, is that ‘no model could grant an independent Scotland frictionless trade with both the EU and the rest of the UK’. That means a visible border between England and Scotland, after centuries without one.

Notwithstanding the economic implications, the potency of that prospect as a campaigning tool for the unionists should not be underestimated – especially when other research by Hanbury suggests that ‘a shared British identity’ would be one of the things Scots would miss most if independence does occur.

The second, on the hard-headed tactical side, the IoG emphasise that Scotland’s path to joining the EU ‘runs through Westminster’. Why? Because the bloc is extremely unlikely to welcome a member who has secured independence through unconstitutional means.

This increases Boris Johnson’s leverage when it comes to refusing a second referendum, or negotiating the terms of one at some point in the future. And this comes just as Salmond and Alba are piling pressure on Sturgeon to adopt a more aggressive constitutional strategy and spell out what she will do if and when the Prime Minister refuses to grant her a Section 30 order.

Nor should we neglect the timescales involved here. As the report spells out, Scotland could only negotiate accession to the EU after formally exiting the UK. Allow that the Government could forestall a referendum until at least the mid-2020s, and that negotiating Scotland’s departure could take five years on top of that, it could be 2030 or later before it was in a position to join.

It doesn’t seem unrealistic to expect that the pull of EU membership might by then be much reduced, ten years on from the memory of being part of it and the rancorous politics of the years after the referendum. Especially not if the Government can follow up the vaccine rollout with a UK-wide economic recovery, and wield its new post-Brexit powers to demonstrate the utility of the Union in every part of the country.<//>