Abdullah Jamal‏‏

On September 14, 2026, the leaders of the Scottish National Party (SNP), Plaid Cymru, and Sinn Féin signed a memorandum of understanding (<a href="https://sinnfein.ie/news/leaders-of-plaid-cymru-snp-and-sinn-fein-agree-memorandum-of-understanding-to-build-towards-constitutional-change/" rel="noopener noreferrer" target="_blank">MoU</a>) in Cardiff, calling on the British government to "prepare for, plan for and facilitate constitutional change" in Scotland, Wales, and Northern Ireland.The agreement marks a significant development in relations among the three nationalist movements. For the first time since the introduction of devolution, all three nations have leaders from nationalist parties seeking fundamental changes to their constitutional relationships with the United Kingdom. Their ultimate objectives, however, differ. The SNP advocates Scottish independence and Plaid Cymru seeks independence for Wales, while Sinn Féin aims to end Northern Ireland’s membership of the United Kingdom and reunify the island of Ireland through political union with the Republic of Ireland.The agreement comes amid renewed pressure for constitutional change. Notably, on October 11, 2026, Scottish First Minister and SNP leader John Swinney reiterated his call for the people of Scotland to <a href="https://www.itv.com/news/2026-10-11/swinney-says-he-and-sturgeon-still-friends-despite-election-campaign-criticism" rel="noopener noreferrer" target="_blank">determine</a> their constitutional future through an independence referendum.Key DriversSeveral political, economic, and constitutional considerations help explain why the three parties signed the Cardiff Agreement, shifting from largely separate campaigns toward greater coordination over the United Kingdom’s constitutional future.1. Upholding the Principle of Self-Determination: The <a href="https://www.holyrood.com/news/view%2Cin-full-the-snp-plaid-cymru-and-sinn-fin-memorandum-of-understanding" rel="noopener noreferrer" target="_blank">memorandum</a> of understanding affirms the right of the people of Scotland, Wales, and Northern Ireland to determine their constitutional futures through democratic means, rejecting the idea that exercising this right should depend entirely on the central government in Westminster.<a href="https://sinnfein.ie/news/leaders-of-plaid-cymru-snp-and-sinn-fein-agree-memorandum-of-understanding-to-build-towards-constitutional-change/" rel="noopener noreferrer" target="_blank">Coordination</a> among the three parties gives these demands a broader political dimension, rather than leaving each constitutional question confined to relations between each nation and London. This does not mean, however, that the parties share identical objectives. Scottish independence differs from the establishment of an independent Welsh state, while both are distinct from Irish reunification. Despite these differences, the agreement seeks to establish common political ground for cooperation despite these differences.2. Nationalist Parties Leading All Three Devolved Governments: The <a href="https://www.theguardian.com/politics/2026/may/09/swinney-keen-to-work-with-fellow-nationalist-devolved-leaders-in-uk" rel="noopener noreferrer" target="_blank">agreement</a> comes at an unusual political moment, with the leaders of Scotland, Wales, and Northern Ireland representing parties that do not regard the existing constitutional arrangements as permanent.These parties aim to turn this <a href="https://www.itv.com/news/2026-09-12/momentum-for-constitutional-change-undeniable-says-swinney" rel="noopener noreferrer" target="_blank">political alignment</a> into a sustained framework for cooperation, breaking down the political silos in which the three individual nationalist movements have tradtionally operated. Such coordination could give their demands for constitutional change a broader UK-wide dimension, enable them to exchange political experience and coordinate their efforts, and keep constitutional reform on the political agenda.3. Increasing Political Pressure on Westminster: <a href="https://www.rte.ie/news/uk/2026/0914/1591410-independence-summit/" rel="noopener noreferrer" target="_blank">Scotland</a> and Wales face legal constraints that limit their ability to pursue independence unilaterally. Northern Ireland, meanwhile, has a different <a href="https://www.legislation.gov.uk/ukpga/1998/47/schedule/1" rel="noopener noreferrer" target="_blank">legal mechanism</a> for holding a referendum on Irish reunification, under which the British Secretary of State for Northern Ireland has a direct role in calling a vote when specified conditions are met.Collective action therefore offers an opportunity to present the three constitutional questions as a broader challenge facing the United Kingdom rather than as separate regional disputes. By urging London to prepare in advance for possible constitutional change, the parties are also sending a political message that these issues cannot be postponed indefinitely.4. Challenging Westminster’s Centralized Economic Model: The Cardiff agreement is not driven solely by nationalism and questions of identity. Opposition to Westminster’s economic <a href="https://www.legislation.gov.uk/ukpga/1998/47/schedule/1" rel="noopener noreferrer" target="_blank">model</a> is also a central theme in the shared agenda of the three parties.They argue for greater control over policies relating to economic growth, employment, inequality, and wealth distribution. Renewable energy is another important element of their economic case for constitutional change. Scotland, Wales, and Northern Ireland possess substantial renewable energy resources, and the parties argue that local communities should receive a greater share of the benefits.They therefore see greater constitutional powers as a means of gaining more control over how these resources are developed and how the resulting revenues are used.5. Reengaging with Europe: The United Kingdom’s withdrawal from the European Union has <a href="https://sinnfein.ie/news/leaders-of-plaid-cymru-snp-and-sinn-fein-agree-memorandum-of-understanding-to-build-towards-constitutional-change/" rel="noopener noreferrer" target="_blank">provided</a> common ground for the parties that signed the Cardiff agreement, particularly given Brexit’s economic consequences and its implications for Scotland, Wales, and Northern Ireland.The parties have therefore highlighted closer relations with Europe as an argument in favor of their respective constitutional ambitions. Although their precise objectives differ—Scottish and Welsh independence on the one hand, and Irish reunification on the other—these outcomes could allow Scotland, Wales, and Northern Ireland to pursue closer ties with Europe, independently of the policies of Westminster.6. Building a Long-Term Framework for Constitutional Change: The <a href="https://sinnfein.ie/news/leaders-of-plaid-cymru-snp-and-sinn-fein-agree-memorandum-of-understanding-to-build-towards-constitutional-change/" rel="noopener noreferrer" target="_blank">memorandum</a> of understanding does not establish a common timetable for referendums. Instead, it acknowledges that each party will pursue constitutional change in its own way and at a time appropriate to its circumstances.For now, the parties appear focused on establishing lasting channels for coordination and sharing expertise in economic policy, energy, and international relations. Over time, these efforts could lay the groundwork for coordinated action to pursue constitutional change, if domestic conditions become more favorable.Challenges to IndependenceDespite the political significance of the Cardiff agreement, translating this coordination into a viable route toward independence or reunification remains difficult.One of the main obstacles is the <a href="https://commonslibrary.parliament.uk/research-briefings/cbp-8544/" rel="noopener noreferrer" target="_blank">absence</a> of a common constitutional process. Northern Ireland has a <a href="https://www.legislation.gov.uk/ukpga/1998/47/schedule/1" rel="noopener noreferrer" target="_blank">legal mechanism</a> for holding a referendum on Irish reunification. Under this framework, the British Secretary of State for Northern Ireland is required to call a referendum if it appears likely that a majority of voters would support reunification.Scotland and Wales, by contrast, have no <a href="https://researchbriefings.files.parliament.uk/documents/CBP-8544/CBP-8544.pdf" rel="noopener noreferrer" target="_blank">equivalent</a> automatic mechanism for pursuing independence. As a result, although the three parties can coordinate their political efforts, they remain subject to different legal procedures for achieving their respective constitutional objectives.Several challenges stand out:1. Continued Legal Obstacles to Scottish Independence: Scotland faces a significant legal obstacle following the UK Supreme Court’s November 2022 <a href="https://supremecourt.uk/uploads/uksc_2022_0098_judgment_5ca161fc9b.pdf" rel="noopener noreferrer" target="_blank">ruling</a> that the authority to legislate for an independence referendum falls within constitutional matters reserved to the UK Parliament. Accordingly, the Scottish Parliament cannot independently legislate for such a referendum.The 2014 independence <a href="https://commonslibrary.parliament.uk/research-briefings/cbp-9104/" rel="noopener noreferrer" target="_blank">referendum</a> was held under an agreement between the British and Scottish governments that temporarily transferred the necessary powers. Under the current constitutional framework, another legally authorized referendum would therefore require Westminster’s consent or an alternative constitutional arrangement.2. Economic and Institutional Challenges to Welsh Independence: Welsh <a href="https://www.gov.wales/independent-commission-on-the-constitutional-future-of-wales-final-report-chapter-8-html" rel="noopener noreferrer" target="_blank">independence</a> faces challenges that extend beyond political and legal considerations to the practicalities of establishing a viable independent state.In this regard, the Independent Commission on the Constitutional Future of Wales identified several unresolved issues, including public finances, currency arrangements, borders, trade, and institutional capacity. Before independence can be implemented, these questions will need to be addressed. Plaid Cymru therefore faces the challenge of setting out a comprehensive and workable vision for an independent Welsh state, including its institutions and economic management, while building broader public support for independence.3. The Need for a Sustained Majority in Northern Ireland: Although Northern Ireland has a <a href="https://aims.niassembly.gov.uk/officialreport/minutesofevidencereport.aspx?AgendaId=38495&amp;eveID=18949" rel="noopener noreferrer" target="_blank">legal</a> mechanism for holding a referendum on Irish reunification, activating it depends on evidence that a majority would support such an outcome. The British Secretary of State for Northern Ireland is responsible for determining when this condition has been met.Sinn Féin’s prospects therefore depend on its ability to translate political support for the party into a stable popular majority favoring reunification. The process would also require agreement on extensive transitional arrangements involving both Northern Ireland and the Republic of Ireland.4. Uneven Public Support for Constitutional Change: Opinion <a href="https://www.ipsos.com/en-uk/growing-public-scepticism-over-uks-long-term-survival-leaders-plaid-snp-and-sinn-fein-meet" rel="noopener noreferrer" target="_blank">polls</a> reveal significant differences in public attitudes across Scotland, Wales, and Northern Ireland.In Scotland, an Ipsos poll conducted in May 2026 showed a closely divided electorate, with 48% supporting independence and 52% opposing it.In <a href="https://www.itv.com/news/wales/2026-09-15/welsh-support-grows-for-burnhams-labour-as-plaid-stays-top-in-senedd" rel="noopener noreferrer" target="_blank">Wales</a>, Plaid Cymru led voting intentions for the Senedd election with 32%, according to an ITV Cymru Wales poll published in September 2026. However, support for Welsh independence stood at only around 20%, indicating that electoral support for a nationalist party does not necessarily translate into support for independence.In Northern Ireland, a May 2026 poll conducted by the Institute of Irish Studies and The Sunday Times <a href="https://www.liverpool.ac.uk/media/livacuk/irish-studies/research/IIS,Sunday,Times,-,NI,Survey,May,2026.pdf" rel="noopener noreferrer" target="_blank">found</a> that 35.8% of respondents would support Irish reunification if a referendum were held the following day, compared with 49.7% who would oppose it. The remainder were neutral or undecided. A separate question in the same survey found that 61.4% supported remaining in the United Kingdom.These differences demonstrate the varying levels of public support for the three constitutional projects. Each nationalist movement must therefore build support for its own objectives, since political momentum in one part of the United Kingdom cannot necessarily be expected to translate into similar gains elsewhere.5. The Economic and Fiscal Costs of Scottish Independence: Fiscal conditions represent a major challenge, particularly for <a href="https://www.gov.scot/publications/government-expenditure-revenue-scotland-2025-26/pages/8/" rel="noopener noreferrer" target="_blank">Scotland</a>, which recorded an estimated fiscal deficit of £25.3 billion, equivalent to approximately 10.9% of GDP, in the 2025–2026 financial year. This compares with a deficit of 4.2% of GDP across the United Kingdom.The <a href="https://www.gov.scot/publications/gers-methodology-2025-26/pages/frequently-asked-questions/" rel="noopener noreferrer" target="_blank">Scottish government</a>, however, emphasizes that these figures reflect Scotland’s finances under the existing constitutional arrangements and should not be treated as a direct forecast of the fiscal position of an independent state.Nevertheless, the figures highlight the importance of the economic and fiscal decisions that would arise during any transition to independence, particularly those involving taxation, spending, borrowing, public debt, and the financing of public services.6. Complex Post-Independence Arrangements: A vote for independence, if held and successful, would not be the end of the constitutional process. Instead, it would mark the beginning of complex negotiations over a range of <a href="https://www.gov.wales/independent-commission-on-the-constitutional-future-of-wales-final-report-chapter-8-html" rel="noopener noreferrer" target="_blank">issues</a>, including currency arrangements, the division of public debt and assets, pensions, defense, citizenship, freedom of movement, cross-border trade, and the future of the UK internal market.Irish reunification would involve a different form of integration but would similarly require extensive political, economic, and institutional agreements.Furthermore, Scotland’s and Wales’s ambitions to establish closer ties with the <a href="https://enlargement.ec.europa.eu/enlargement-policy/conditions-membership_en" rel="noopener noreferrer" target="_blank">European Union</a> would not automatically grant them EU membership following independence. Both would need to follow the relevant accession procedures. Northern Ireland, by contrast, is in a different position, because reunification with the Republic of Ireland would bring it into a state that is already an EU member.ConclusionThe Cardiff Agreement represents an attempt by nationalist parties in Scotland, Wales, and Northern Ireland to strengthen cooperation and &nbsp;move beyond separate political campaigns toward a joint framework for pursuing their constitutional demands.Its immediate impact, however, is likely to remain limited. The agreement does not change existing constitutional rules or guarantee that referendums will take place. These nationalist movements must also contend with varying levels of public support, alongside distinct legal and political challenges.For now, the agreement’s main significance lies in its potential to keep the United Kingdom’s constitutional future on the political agenda and strengthen coordination among the three parties, rather than signaling that fundamental constitutional change is imminent.The prospects for independence or reunification will continue to depend on a number of variables. Although their relative importance will vary across the three nations, three main factors will shape the trajectory of these nationalist movements: how public opinion evolves; how the British government responds; and the extent to which each party can present a credible and workable vision for its nation’s future outside the UK.&nbsp;

Can Scotland, Wales, and Northern Ireland Break Away from the United Kingdom?