Chris McCorkindale and Aileen McHarg: Constitutional Pathways to a Second Scottish Independence Referendum

The Scottish Government’s Case for a Second Independence Referendum

On 19 December 2019 – a week after the Westminster General Election at which the SNP, again, won an overwhelming majority of Scottish seats – the Scottish Government published its long-awaited case for a second independence referendum: Scotland’s Right to Choose: Putting Scotland’s Future in Scotland’s Hands

The document does three main things, aimed at four distinct audiences. First, the bulk of the discussion is devoted to setting out the democratic case for holding a second referendum by the end of 2020. This is based on three claims: that the people of Scotland, as members of a multi-national Union based on consent, have the sovereign right to determine their own constitutional future; that there has been a material change in circumstances since the 2014 referendum; and that the Scottish Government has a mandate to hold a referendum. The material change in circumstances is said to be the fact that Scotland will be leaving the European Union despite the desire of the majority of Scottish voters to remain, combined with what the Brexit process has revealed about Scotland’s place within the UK. The Scottish Government’s mandate derives from its victories at the 2016 Holyrood election, and the 2017 and 2019 Westminster elections, combined with a majority vote in the Scottish Parliament on 28 March 2017. The main audience for this part of the document is soft Unionist supporters in Scotland and beyond. It seeks to persuade them that it would be undemocratic for the UK to continue to refuse to facilitate a second referendum, thereby drawing attention to the SNP’s central constitutional argument for independence: the continuing democratic deficit in the governance of Scotland.

The second aim of the document is to make the case for a second referendum to be held on a consensual basis, and for co-operation by the UK Government in putting its legality beyond doubt. The document refers to the precedent of the October 2012 Edinburgh Agreement, in which the UK and Scottish Government agreed on the conditions for a legal, fair and decisive referendum, and which led to a temporary amendment of the Scotland Act 1998 via an Order under section 30 of that Act to enable Holyrood to enact authorising legislation. The main audience here is two-fold. First, the Scottish Government’s own supporters, some of whom are impatient with what they see as its excessively cautious approach to securing independence. Second, the EU institutions, for whom the legality (as well as the consensual nature) of the process might condition any future relationship with an independent Scotland.     

Finally, in Annex B, the document sets out draft amendments to the Scotland Act – to be made either by another section 30 Order or by primary legislation – to secure the necessary transfer of competence. These go significantly beyond what was agreed in 2012. First, they include an explicit statutory recognition of Scotland’s right to self-determination. Second, they would permanently amend the Scotland Act to make it clear that Holyrood has competence to authorise an independence referendum. Third, they make provision for implementing a vote for independence by placing a statutory duty on the UK and Scottish Governments to co-operate in securing the transition to independence, and by extending the legal competence of the Scottish Parliament, Scottish Ministers and other public authorities to prepare for independence. Clearly aimed at the UK Government, these proposed amendments may more accurately be seen as an invitation to treat rather than a realistic expectation of what might be agreed. Indeed, unionist parties in Scotland are likely to want to place more conditions on a second referendum than on the first – for instance, control over the referendum question, or requiring a special majority to trigger a vote.

Although the UK Government is yet to formally respond to the Scottish Government’s request, the indications are that it will not agree to a referendum in 2020, although it is unclear whether it will reconsider – for instance, after the 2021 Holyrood General Election. Assuming that it does continue to refuse to cooperate, where does that leave the prospects for a second referendum? In the remainder of this post, we consider, first, why the legality of a referendum – and, by extension, the process of becoming independent – matters; secondly, we consider the options that may be open to the Scottish Government to secure a lawful referendum.

Why Does Legality Matter?

A state may become independent in one of two ways: either with the consent or at least acquiescence of the parent state, in accordance with its domestic constitutional requirements, or via a unilateral declaration of independence (UDI). Although the International Court of Justice recognised in its 2010 Kosovo Reference that UDI is not contrary to international law, it is a less certain and less satisfactory route to independence. This is because achieving effective independence is a matter of securing recognition by other sovereign states, including the parent state, and this, as the ICJ pointed out, is essentially a political rather than a legal matter. In effect, international recognition is much more likely to be forthcoming if the independence process is perceived to have been legitimate. As Scotland’s Right to Choose clearly acknowledges (p 20),

When they make a decision about their future, the people of Scotland must do so in the knowledge that their decision will be heard and respected and given effect to: not just by the government in Scotland, but also by the UK Government, by the European Union and by the international community.

For a referendum to have this legitimacy, it must have the confidence of all of those that it would effect (sic). This means not just the UK Government acknowledging and respecting the Scottish Government’s mandate, but the Scottish Government and UK Government seeking to agree the proper lawful basis for the referendum to take place.

As a matter of UK constitutional law, Scotland can only become independent with the agreement of the UK Parliament – whether that agreement is explicit and direct, via specific legislation granting independence; indirect, via a general transfer of competence to secure independence to Holyrood; or implicit, if the authority to seek independence can already be found within the terms of the Scotland Act 1998. As a matter of law, a referendum is not a required part of the process of becoming independent. However, it is at least arguable that, in a conventional sense, it is a constitutional requirement, given the precedent of the 2014 independence referendum, the provisions for a border poll on Irish reunification in the Northern Ireland Act 1998, and the statutory referendum ‘lock’ against unilateral abolition of the Scottish Government and Scottish Parliament by the UK Parliament in the Scotland Act 2016. The House of Lords Constitution Committee in its 2010 report on Referendums in the United Kingdom (para 94) also took the view that it was at least appropriate for a referendum to be held on questions of secession by any of the nations of the UK from the Union.

If a second independence referendum is to take place and be effective as a means of achieving independence it is therefore crucial that it be conducted on a proper legal footing – that is, that the rules it sets out providing for the organisation of a poll and regulating the conduct of the referendum campaign are legally valid and hence binding on those to whom they apply. This is a separate – and a more important – issue to the legal effect of the referendum result. The 2014 referendum was advisory only – it did not legally bind the UK or Scottish Government to give effect to a vote for independence – but it was legally valid because it was conducted on the basis of legislation enacted by Holyrood after its competence to enact such legislation had been confirmed by the section 30 Order (the Scottish Independence Referendum Act 2013 and the Scottish Independence Referendum (Franchise) Act 2013 – both of which are now spent). Attempting to proceed with a referendum without such a legislative underpinning would be a non-starter, given that it would depend upon the co-operation of Scotland’s 32 local authorities in organising the vote (none of which is under majority SNP control), and would almost certainly be boycotted by unionists. 

A Referendums (Scotland) Bill completed its passage through the Scottish Parliament on the same day as Scotland’s Right to Choose was published. This provides a general legal framework for referendums within devolved competence, similar to, but in some respects going beyond, the Political Parties, Elections and Referendums Act 2000 (which only applies to referendums authorised by Westminster). However, in order to be applied to any particular referendum, further specific authorising legislation is required.

Although it is frequently asserted that a referendum on independence falls outwith devolved competence (as part of the reservation to Westminster of “the Union of the Kingdoms of Scotland and England”, Scotland Act 1998, Schedule 5, Part 1, para 1(b)), that issue has never been conclusively settled. Nevertheless, any attempt to legislate for a referendum without a further explicit transfer of power is certain to be challenged in the courts; could cause significant difficulties within the Scottish Government, possibly including resignation of the Scottish Law Officers; and might also provoke retaliatory legislation from Westminster to make clear that such legislation is not within Holyrood’s competence, similar to the fate of the UK Withdrawal from the European Union (Legal Continuity) (Scotland) Bill. Moreover, even if such a Bill were to survive, a unilateral approach to authorising a second referendum might again lead to a unionist boycott and could not be certain of co-operation from the UK Government in implementing a vote for independence.

Securing a Lawful Referendum

Unpalatable as it may be to some nationalists that the exercise of Scottish self-determination depends on Westminster’s co-operation, it is hard to avoid the conclusion that this is necessary. What, then, if anything, might be done to secure that co-operation?

It has been suggested that, should the UK Government refuse to accede to the request for a transfer of legislative competence, a legal challenge might follow – and indeed a crowdfunder has already been launched with such litigation in mind. It is, however, extremely unlikely that such a challenge would be successful, since there is no duty to make a section 30 Order, still less to introduce primary legislation. The crowdfunder makes vague reference to the case being brought on the basis of the right of the Scottish people to self-determination. But it is at least implicit in the Scottish Government’s request for statutory recognition of this principle that it does not currently form part of UK or Scottish constitutional law – even if it has plenty of endorsement in constitutional practice. This contrasts with Northern Ireland, where the “principle of consent” is explicitly recognised in the Good Friday Agreement, and given statutory expression in section 1 of the Northern Ireland Act 1998. Similarly, while international law does recognise a right of national minorities to self-determination which may, in some circumstances, include a right to secede from the parent state, the Supreme Court of Canada concluded in its Quebec Secession Reference that this does not apply in the case of national minorities such as Quebec and also Scotland which already enjoy a high degree of internal autonomy and political representation.

Similarly, the Scottish Government’s mandate to hold a referendum – though politically important – seems legally irrelevant. The doctrine of the mandate plays, at best, a marginal role in UK constitutional law and practice, and in any case what constitutes a mandate is highly ambiguous: how clear does a manifesto promise have to be; is a majority of seats or of votes required (and can these be aggregated from more than one party); and which elections are relevant – to the UK Parliament, which holds the legal competence to dissolve the Union, or the Scottish Parliament, from which the Scottish Government’s authority derives? Other, more standard grounds of judicial review – legitimate expectations based on the precedent of the Edinburgh Agreement, irrationality, or failure by the UK Government to give adequate reasons for the rejection of any request – also seem likely to fail. Again, this contrasts with the position in Northern Ireland, where it was recently held (In Re McCord at [20]) that, in relation to the Secretary of State’s duty to hold a border poll under section 1 and Schedule 1 of the Northern Ireland Act 1998, she must “honestly reflect” on whether the statutory conditions (that it is likely that a majority would vote for Irish reunification) are met.

In light of these difficulties, another option that has been proposed by some in the SNP ranks is to bypass a second referendum altogether. This so-called ‘Plan B’ urges the Scottish Government to take the return of a pro-independence majority to Holyrood in 2021 as a mandate directly to enter into independence negotiations with the UK Government. For a number of reasons, this is unlikely to succeed. First, the Scottish Government has rejected this approach in Scotland’s Right to Choose, whilst the SNP leadership has also done so in the defeat of a motion to debate this alternative path at the 2019 party conference. Second, the pursuit of independence via this route fails to avoid the power dynamics behind the referendum dilemma. Any such approach would require the UK Government willingly to join those negotiations, something that seems unlikely without clear and unambiguous popular endorsement. Third, in the absence of a mutually agreed and regulated process of participation robust enough to cultivate losers’ consent, this approach is highly unlikely to be “accepted as legitimate in Scotland, the UK as a whole, and by the international community” (p 1).

So much for what the Scottish Government cannot do, or ought not to do. What can it do proactively to advance its position? Strategically, it is likely that the Scottish Government has always anticipated that the UK Government will reject its call for a referendum in 2020. Instead, there seems to be an attempt to frame any such rejection – and the democratic case more broadly – as the central issue of the 2021 election to the Scottish Parliament. Whilst, as a matter of law, the UK Government might continue to withstand the pressure of a renewed pro-independence majority at Holyrood, there have been signs even in unexpected places – notably from within the UK Government itself as well as from within Scottish Labour – that the legitimacy of such a result would be difficult to resist. Tactically, the SNP might rely on its Westminster membership to maintain political momentum towards – and to finesse the legal form of – a referendum. It could do so with the introduction of a Private Members’ Bill in the form set out in Annex B. Such a Bill would almost certainly fail to be passed. However, and as advocates for an EU referendum discovered prior to the UK Government’s introduction of the EU Referendum Bill in 2015, these Bills can usefully be deployed both to give life to – and to stress test – proposed legislation; to signal action to an impatient audience; as well as to emphasise the sites of political obstruction when the Bill falls. That cohort might also use the advantages of being the third largest party at Westminster – including increased opportunities to make use of opposition time or to ask questions of the Prime Minister at PMQs – to provoke a response from the UK Government. At Holyrood, the SNP – working with the assistance of Greens and other parties opposed to Brexit – might see the legislative consent mechanism as one way to re-state the argument from democratic deficit, as it has done this week when the Scottish Parliament refused legislative consent in relation to the European Union (Withdrawal Agreement) Bill 2019-20.

Political pressure might also emerge outside of these formal political institutions – from public protest or from civic initiatives such as the 1989 Claim of Right or the Scottish Constitutional Convention which preceded the formal act of devolution. Indeed, on the same day that the First Minister announced her government’s intention to pursue a referendum by 2021 she announced also the establishment of a Citizens’ Assembly for Scotland that would examine the sort of country, independent or otherwise, that Scotland wants to build.


Whether there is a second referendum – and if so, on what terms – is a political question that will be resolved in the political arena. There are no legal short cuts through that space. However, just as there is no legal right to insist upon Scotland’s independence or its competence to hold a referendum, nor is there – contrary, for example, to the Catalonian experience – any legal obstacle to independence if the political argument can be won. It is not only in this passive sense that law matters. A negotiated approach to establish a sound legal footing is likely to come at a cost, be that the insertion of conditions by the UK Government or the passage of time as agreement is sought and concluded. However, as Scotland’s Right to Choose makes clear, a referendum that has a clear legal basis, agreed to between governments, that is regulated by law and consistent with democratic and rule of law values is the surest – perhaps the only – way to deliver a result that is fair, decisive, and accepted as legitimate at home and abroad.

Chris McCorkindale, Senior Lecturer in Public Law, University of Strathclyde

Aileen McHarg, Professor of Public Law and Human Rights, University of Durham

(Suggested citation: C. McCorkindale and A. McHarg, ‘Constitutional Pathways to a Second Scottish Independence Referendum’, U.K. Const. L. Blog (13th Jan. 2020) (available at