Iain Halliday: Can the Scottish Parliament Legislate for a Second Independence Referendum?

Following the December 2019 election result, which resulted in the Conservative party winning an overall majority, but losing several of their seats in Scotland to the SNP, there has been renewed calls for a second referendum on Scottish independence.

There is an ongoing debate regarding whether the Scottish Government and Parliament can hold a referendum without the consent of the UK Government and Parliament. The reason this is uncertain is because the Scottish Parliament cannot pass whatever legislation it wishes to pass in the same way the UK Parliament at Westminster can. It can only pass legislation if it does not relate to a “reserved matter”. The Scotland Act 1998 lists the various matters which are reserved.  One such matter is “the Union of the Kingdoms of Scotland and England”.

So the question is, would an Act of the Scottish Parliament providing for a second independence referendum “relate to” the Union of the Kingdoms of Scotland and England? Whether a provision relates to a reserved matter is to be determined by reference to the purpose of the provision, having regard (among other things) to its effect in all the circumstances.

This questions was left without an answer in the lead up to the 2014 referendum as the UK Government agreed to confer competence upon the Scottish Parliament for a limited period through what is referred to as a section 30 Order. For the reasons previously highlighted on this blog, a similar approach for a second referendum would be preferable.

However the UK Government seems unwilling to repeat this course of action and so the debate has, once again, become relevant. Some have claimed that the issue has been settled by the passing of the Referendums (Scotland) Act 2020, however this Act merely implements a legal framework for the holding of referendums in Scotland; it does not provide for any particular referendum, on any particular issue, to be held.  Further legislation would be needed to make provision for a second independence referendum. So what would the purpose of that legislation be, having regard to its effects in all of the circumstances?


In relation to purpose it has been argued that there could be numerous reasons why the Scottish Parliament (as distinct from the Scottish Government) may wish to pass legislation allowing a referendum on Scottish independence. For instance many MSPs may vote for such legislation to put the matter to rest for the foreseeable future (or at least until a further change of circumstances justifies a renewed call for independence). Parliament’s intention would not necessarily be to dissolve the Union. The Government’s political motivation for passing legislation is not the same as its purpose. 

A great deal of deference is afforded to the Scottish Parliament:

“…the elected members of a legislature… are best placed to judge what is in the country’s best interest as a whole. A sovereign Parliament is, according to the traditional view, immune from judicial scrutiny because it is protected by the principle of sovereignty. But it shares with the devolved legislatures, which are not sovereign, the advantages that flow from the depth and width of the experience of its elected members and the mandate that has been given to them by the electorate. This suggests that the judges should intervene, if at all, only in the most exceptional circumstances” – AXA General Insurance Ltd v HM Advocate [2011] UKSC 46 at para 39)

Given this general reluctance to interfere with the decisions of a democratically elected parliament, and the requirement that Acts of the Scottish Parliament are read “as narrowly as is required for it to be within competence, if such a reading is possible”, the Supreme Court may be hesitant to declare legislation providing for a second independence referendum unlawful.  

On the other hand, it could be argued that the SNP’s political purpose in introducing legislation for a second independence referendum would be highly relevant when considering the legal purpose of that legislation. The intention of the Scottish Government is indisputably clear: they want Scotland to be an independent country. The purpose of the referendum would clearly be to achieve a ‘Yes’ vote and deliver independence (i.e. dissolve the Union between Scotland and England, which is a reserved matter), not simply to conduct a market research exercise.

The purpose of the Scotland Act 1998 itself is also of relevance. This is determined primarily with reference to the text, including headings:

“In deciding what that provision is intended to reserve, it is necessary to take account of its statutory context, including the heading of paragraph 1: Imperial Tobacco, para 17. As we have mentioned, paragraph 1 is headed “The Constitution”. It reserves five aspects of the constitution. They are all fundamental elements of the constitution of the UK, and of Scotland’s place within it: the Crown, the Union, the UK Parliament, and the existence of Scotland’s higher civil and criminal courts.” – The UK Withdrawal from the European Union (Legal Continuity) (Scotland) Bill Reference [2018] UKSC 64 at paragraph 60

However the court can also consider the wider context of legislation, including statements made in parliament during passage of the Act, to determine its meaning and purpose. The purpose of the Scotland Act was to create a limited legislature; and it is fairly clear from the parliamentary debates during passage of the Act that the reservation of “the Union of the Kingdoms of Scotland and England” was intended to ensure that a referendum on Scottish independence would be outwith those limits. Whilst not determinative, the fact that the Westminster Parliament did not intend to confer the power to hold a referendum on independence upon the newly established Scottish Parliament is likely to be given weight when interpreting the provisions of the 1998 Act.


In relation to the effect of a second independence referendum, as the referendum would be advisory, it has been argued that the effect would not be to break up the United Kingdom. Such an outcome would also only occur in the event of a ‘Yes’ vote. Even if this were to occur dissolution of the Union would take place separately, at a later date, under separate legislation (which would need to be passed at Westminster). The referendum merely determines whether the Scottish people wish to take this separate step.

This interpretation is supported by the Supreme Court’s decision in Miller (No. 1) which highlighted that the effect of any particular referendum must depend on the terms of the statute which authorises it. For several other referendums the relevant legislation has stipulated what should happen in response to the referendum result, and what changes in the law were to follow, and how they were to be effected. The legislation providing for the Brexit referendum in 2016 did not.

The UK Government argued that:

“…having referred the question whether to leave or remain to the electorate, Parliament cannot have intended that, upon the electorate voting to leave, the same question would be referred straight back to it.” –Miller & Anor v Secretary of State for Exiting the European Union [2017] UKSC 5 at paragraph 120

This was rejected by the Supreme Court, which held that the Brexit referendum had not changed the law and that Parliament was required to legislate to authorise the start of the Brexit process (which they subsequently did).

The Supreme Court concluded that:

“…the referendum of 2016 did not change the law in a way which would allow ministers to withdraw the United Kingdom from the European Union without legislation. But that in no way means that it is devoid of effect. It means that, unless and until acted on by Parliament, its force is political rather than legal. It has already shown itself to be of great political significance.” – Miller & Anor v Secretary of State for Exiting the European Union [2017] UKSC 5 at paragraph 124

Applying this argument to the context of Scottish independence, it could be said that a vote in favour of Scottish independence, although of great political significance, would have no legal effect (assuming the legislation was silent on the effect of a ‘Yes’ vote) and, as such, would not relate to the reserved matter of the Union. Westminster would need to legislate to implement the outcome of the referendum, in the same way that it did following the Brexit referendum.

On the other hand, it can be argued that there is nothing to suggest that the “effect” of an Act of the Scottish Parliament is to be understood in a strictly legal sense. The effect must be considered “in all the circumstances”. The political effect of a Yes vote following another Scottish independence referendum would clearly be to bring an end to the Union between Scotland and England. Arguably such a vote could create a legal obligation requiring UK Ministers to commence negotiations to bring about independence, as was the case with the Quebec Secession Reference in Canada.

The Supreme Court had this to say about the Brexit referendum:

“As everyone knows, a referendum was held (pursuant to the European Union Referendum Act 2015) on 23rd June 2016. The majority of those voting voted to leave the European Union. Technically, the result was not legally binding. But the Government had pledged to honour the result and it has since been treated as politically and democratically binding. Successive Governments and Parliament have acted on that basis”. (Miller & Cherry v The Prime Minister [2019] UKSC 4)

Would a Scottish independence referendum be treated any differently? Perhaps it would, if it was made clear, and widely accepted, prior to the vote taking place that it was not politically or democratically binding. However if that is to be the case, what is the point in having the vote in the first place?

A great deal of emphasis is often placed on this line of argument, however it is worth bearing in mind that:

“The effect of a provision is merely one of the circumstances to which the court must have regard when determining the purpose.” (SEPA and others v Scottish Coal Company Ltd and others [2013] CSIH 108 at paragraph 150)

As such the effect of the referendum is unlikely to be decisive when determining the purpose of the relevant legislation, particularly given that the effect cannot be known until the vote takes place and the outcome declared. 


Ultimately it will be up to the Supreme Court to decide the issue, if called upon to do so. Given Nicola Sturgeon’s dogged determination to hold a second referendum within the next couple of years, and Boris Johnson’s summary dismissal of any call for recognition of Scotland’s distinctive place within the Union, it seems likely that we will not need to wait too long to find out the answer.

Iain Halliday is an Associate Solicitor at McGill & Co Solicitors.

(Suggested citation: I. Halliday, ‘Can the Scottish Parliament Legislate for a Second Independence Referendum?’, U.K. Const. L. Blog (13th Feb. 2020) (available at https://ukconstitutionallaw.org/))