The supreme court is due to rule on Wednesday whether the Scottish parliament has the power to approve a referendum on independence without Westminster’s approval.
A panel of five justices heard legal arguments from the UK and Scottish governments during a two-day hearing in London last month after First Minister Nicola Sturgeon set out plans to hold a vote on 19 October 2023.
The Westminster government has repeatedly refused to meet the first minister’s demand for another referendum, arguing that the matter was settled for a generation by the 2014 referendum in which Scots voted to stay in the union by 55 to 45 per cent.
Ms Sturgeon’s Scottish National Party points to shifting opinion polls which, though they rarely show majority support for independence, have narrowed significantly in the past eight years. The SNP also says its majority in Holyrood, won on the promise of holding a referendum, is a democratic mandate for a vote.
The supreme court, which considers the UK’s biggest constitutional questions, was asked to consider whether the Scottish government’s proposed legislation allowing an independence vote is within the power of Holyrood – or as judges might say: “within its legislative competence” – or whether such decisions are reserved to Westminster.
There are several possible rulings the judges could make.
Referendum is within legislative competence of Holyrood
The Scottish government has said that, should a referendum be within the power of the Scottish Parliament, legislation will be introduced and likely passed by the SNP and Scottish Greens.
But, according to legal expert Dr Andrew Tickell, the UK government and other opponents of separation would still not be powerless to stop another vote.
He said the Conservative government could still use their Commons majority to block Holyrood’s legislation “as a matter of law”.
Dr Tickell added that the possibility of a boycott by opposition parties to any referendum would “create a whole range of interesting implications”.
Opposition parties could claim that any vote taken under a boycott would not legitimately represent the views of the Scottish public.
Scottish Tory leader Douglas Ross has been the main proponent of such a strategy.
Holyrood cannot hold a referendum
If the court rules Holyrood cannot hold a referendum, hopes of a vote without Westminster consent are dashed.
The Scottish Government will be forced to continue pushing for a Section 30 order that would provide Holyrood with the necessary powers to call another vote.
Boris Johnson refused Ms Sturgeon’s last request for a Section 30 order earlier this year and current Downing Street resident Rishi Sunak would likely do the same.
One of the more interesting possibilities would be if the court decides not to rule on the referral because the bill has not been passed by Holyrood – a key plank of the UK Government’s argument against the referral.
Constitutional law Professor Adam Tomkins, who served as a Tory MSP in the last parliament, said he viewed this option as the most likely.
“The Scotland Act provides for a system of referring the legislative competence of Bills passed by the Scottish Parliament to the Supreme Court after they have been enacted,” he told the PA news agency, continuing: “In this instance, not only has the Bill not been enacted, it hasn’t even been formally introduced into the Scottish Parliament.”
Prof Tomkins said the Lord Advocate, Dorothy Bain KC, was asking the court to rule on “a hypothetical”.
If the court refused to rule, a number of different possibilities open up to the Scottish government.
First, it could push ahead with the legislation and fight a Supreme Court challenge after its passage – but that would likely result in the resignation of Ms Bain as the government’s chief legal officer, according to Prof Tomkins, which renders the approach the least likely.
Second, it could amend the ministerial code to say that in most circumstances, the Lord Advocate would have to deem the bill within the competence of the Scottish Parliament, therefore allowing the legislation to be introduced.
Or finally, it could pass the Bill to a high-ranking SNP member to introduce, given the less stringent legal requirements of members’ bills.
Referral not valid but court answers anyway
As was done with a legal challenge over abortion in Northern Ireland in 2017, the court could decide to answer the substantive question, while also accepting that the Lord Advocate did not have the powers to refer the draft bill to the Court.
Any decision made in such a situation, Dr Tickell said, would not be legally binding, but would likely be treated as such.
Additional reporting by Press Association