The penny is slowly dropping in Westminster. Brexit and Covid-19 may have been traumatic episodes, but their lasting effect may be existential to Great Britain if, as many now fear, they lead to the loss of Scotland and the break-up of the Union. Opinion polls show 55 per cent supporting independence and they predict sweeping SNP gains in May should the major unionist parties choose to run against each other and split the vote – something that the Alliance for Unity is seeking to prevent.

English nationalists who have fallen for the SNP deploying that most irritating of parliamentarians, the “champagne separatist” Ian Blackford, to make the chattering classes think that life might be better after all without the whingeing jocks, have not thought things through. A weakened Britain, no longer technically “Great” – which was adopted in Article I of the 1707 Act of Union – would be a very sorry realm and a tragic closing chapter to the reign of Queen Elizabeth II. Unable to defend the northern approaches, or hide nuclear submarines in sea lochs, no longer an oil producer, shorn of over a third of its landmass and probably with a government that had lost all authority if not actual power at one of the most vulnerable times in our history, there would be little for Little Englanders to celebrate.

Boris Johnson can stick to the line that the 2014 referendum was a once in a generation event but even staunch unionists concede that may be untenable in the face of persistent non-cooperation from Holyrood and carefully orchestrated civil disobedience leading to the Ulsterisation of Scotland. And many believe that it would be preferable to risk a second and final vote – as happened in Quebec – than have another four years of hate filled “neverendum”. How the Prime Minister must wish that Tony Blair had listened to Tam Dalyell’s warning about devolution being a “motorway, without exits, to independence”.

It never occurred to anyone in 1707 that the Union would ever be severed democratically

The post-modernist fake history deployed by nationalists with the help of Mel Gibson has somehow embedded the notion that the Union was a one-sided affair resulting from the conquest and subordination of Scotland as some sort of colony. The truth of course was that the Stuarts were primarily Scottish, even if they subsequently preferred the pleasures of Newmarket. And possibly because, unlike the Unions with Wales and Ireland, this was a genuine marriage of equals when the parliaments of England and Scotland voted themselves out of existence and the two kingdoms merged into one, most other institutions, the church, the judiciary and, later, football teams, were kept separate and the idea of two separate nations was perpetuated in a way that it was not in Prussia and Hanover. That has lent the illusion of legitimacy to the decentralising dynamic.

Another unfortunate deficiency has been the lack of any provisions for secession. It never occurred to anyone in 1707 that the Union would ever be severed democratically. The threat at the time was from Jacobite invasion. The legislators themselves, but by no means everyone, probably also didn’t want to contemplate the Union ever ending; it had been asked for partly to end a bitter trade war in which an English ship had been seized by the Scottish authorities and the crew hanged on a trumped up charge of piracy. They did not want to invite any return to hostility.

We pride ourselves on having an unwritten constitution but sometimes these things are better written down for the avoidance of doubt. As we now all know, the EU did not allow this omission, possibly that strengthened their union and made it harder to leave but certainly it meant that the Brexit debate was based on known unknowns. By contrast the Scottish separatist debate is largely based on unknown unknowns because the rules of secession have never been codified. The Canadians had the same issue and, following the Quebecois referenda, passed a Clarity Act in 2000 to establish the rules for any future secession referendum.

The Alliance for Unity is now calling on the government to bring in similar legislation. We believe legislative weakness in the lead-up to the 2014 referendum has allowed a loophole to be exploited to allow separatists to voice endless demands for a re-run and kept Scotland shackled to the hamster wheel of “neverendum”. And we believe the rules must be properly debated in Parliament rather than hastily thrown together in an ad hoc fashion in deals with the separatists as happened prior to 2014.

Such a move would no doubt provoke howls of faux constitutional outrage from Holyrood – although the SNP “government” is quite happy to pass legislation itself on this issue – but the fact remains that the UK Parliament with its fifty nine Scottish MPs remains sovereign and is the only place where this legislation can legitimately be executed. There are eight questions that need to be answered.

First there must be a defined procedure for requesting a referendum. What criteria must be met? Nicola Sturgeon claims a “mandate” for Indyref2 on the basis of a majority of seats but there has never yet been a majority of the popular vote for separatist parties in an election. That mandate must be defined.

The SNP would give the vote to a sixteen year old criminal, but the captain of the Scottish football team would be disenfranchised

Secondly the franchise and by extension citizenship. Prior to the 2014 vote, concessions were made to the separatist side, who had lobbied for the voting age to be sixteen despite remaining eighteen for general elections. The SNP would give the vote to a sixteen year old criminal, born overseas but residing in a young offenders’ institute, but the captain of the Scottish football team, who invariably plays for an English Premier League club, would be disenfranchised. The ad hoc nature of the legislation also meant that Scottish servicemen serving outside Scotland were denied a vote on a referendum that would have turned them into foreign mercenaries in the British Armed Forces.

Most seriously, the Scottish diaspora spread across the UK was denied a vote in a referendum that might have deprived them of British citizenship. Since Article XXV of the Act of Union repealed the English Alien Act that treated Scots as, well, aliens, there has been freedom of movement across the UK and a shared citizenship. Like nearly every generation of our family before them, my children are enjoying their young adult life in London hopefully before returning home to Scotland, as I did. Current proposals for any independence referendum would deny them a vote on their futures. These inconsistencies must surely at least be properly addressed in Parliament rather than haggled over in the run-up to a vote.

Thirdly we believe the wording of the question should reflect the seriousness of the decision. The Cameron government believed that by giving Salmond every advantage, including the Yes side of the argument, if, as they confidently believed, the answer was still No, the victory would be all the more convincing. Unfortunately it hasn’t worked out that way and asking Scots yes or no whether they think Scotland should be an independent country has created an unfortunate precedent. Asking Scots whether they wish to leave or remain in the United Kingdom would be a more accurate and appropriate question.

Fourthly we believe there should be a clearly defined minimum requirements for the threshold and the turnout. The fifty percent threshold set in 2014 was historically low compared to similar referenda around the world, and indeed for changes to the SNP constitution. Had there been a very small margin for independence on a low turnout it might have resulted in a majority of Scots being bitterly resentful of being deprived of their British passports.

There is a democratic deficit in Scotland

Much would depend on whether it was planned as a one phase or two phase vote and this is linked to the fifth question over whether Scotland should be treated as one homogeneous entity – as it was at the time of the Union – or allowed to vote regionally. A second confirmatory vote would give Unionist Orkney, Shetland, Dumfries and Galloway and Borders and perhaps other areas, all of which are now actively discussing separation from Scotland, the opportunity to opt back into the United Kingdom. The alternative could be plunging a newly independent Scotland into a secessionist nightmare as the former kingdoms and principalities protest against “being dragged out of the Union against their will.” There is a democratic deficit in Scotland: rural Scotland seldom gets the government it votes for as the population is skewed towards the urban central belt. It would be better to give our citizens a chance to rectify that at the time of the vote.

A phased vote might also help Scots decide their futures based on known knowns rather than the current unknown unknowns. Questions six and seven relate to the two areas that have caused most heat in Brexit: debt and trade. SNP Scexit planning currently makes the blithe assumption that Scotland would be allowed simply to walk away without any share of the national debt, lending new meaning to the expression “Scot free”.

Parliament needs to express its decision clearly on how, or less likely if, the UK national debt would be apportioned before Scotland could be recognised as an independent nation with powers to borrow herself. Similar assumptions are made about trade and the question of a hard border. There was one prior to 1707, would there be again? We don’t know and the mechanisms for agreeing future trading arrangements must be clearly laid down. Allied to this is the question of currency but that seems to have been settled, at least as far as England is concerned: the Scottish treasury would have to make its own arrangements.

Finally, question eight relates to the provision for any future vote in the event of a decision to remain in the Union. Clearer rules on the minimum elapsed time before another referendum and the conditions to be met would avoid a repeat of the six year “neverendum” we have just endured.

The Alliance for Unity is asking Parliament to enact this legislation urgently while no independence referendum is in prospect. You never know, clarity of the planning assumptions for separation might help to avoid having one altogether.