The United Kingdom: A Constitution Under Strain

After the loss of its overseas empire, issues such as devolution and national identity continue to strain the legal frameworks that constitute the United Kingdom. Attitudes towards the autonomy of each constituent nation appear to change with each successive Prime Minister. Further, conflicting opinions over Brexit highlight internal frictions within the UK’s institutional structure, raising concerns as to what degree the United Kingdom can continue as a kingdom united.

The United Kingdom (UK) has transitioned from being an imperial power to a middle power with an economy that is increasingly losing momentum. Having formerly presided over a vast empire, the UK finds itself grappling with issues associated with borders, national identity, as well as significant constitutional uncertainty over devolution, sovereignty, and political legitimacy.

The subject of the UK’s territorial integrity and the self-determination movements in Scotland and Wales, as well as the subject of Irish reunification in Northern Ireland has given rise to heated political debate about independence. The UK was not shaped by a single constitutional instrument, it evolved gradually through successive Acts of Union and constitutional provisions. On this basis, the UK is often depicted as a multi-national state or a State of Unions. Consistent with this account, the Cabinet Office identifies four constituent nations, England, Scotland, Wales, and Northern Ireland, that make up the UK (Torrance, 2026).

Four Nations, One State: A Legal Analysis 

Wales integrated into England through the Laws in Wales Act of 1535 and 1542, subsequent to the 1284 annexation by the English Crown pursuant to the Statute of Rhuddlan or Statutes of Wales. In accordance with existing provisions, England and Wales are viewed as distinct territorial units, subject to specific legal provisions governing Wales’s boundaries as well as the historical significance of statutory references to England in prior Acts (Torrance, 2026). 

The Wales and England union as stipulated in Schedule 7A, Part 1, para 1(b) of the Government of Wales Act 2006, rests with the Westminster Parliament (Wales Act 2017: Explanatory notes, 2017; Government of Wales Act 2006, 2006, sch. 7A, pt. 1, para. 1(b)). For this reason, the Senedd/ Welsh Parliament (Vote Wales, 2026), lacks the statutory authority to amend that union without the approval of the UK Parliament (Welsh Government, 2026). Wales therefore lacks a legal provision to spearhead an independence referendum. Furthermore, any referendum would require the transfer of the legislative competence from Westminster (Paun et al., 2026).

England and Scotland remained separate kingdoms following the 1603 Union of the Crowns,  but shared a monarch until the Acts of Union 1707 integrated them into a single kingdom, Great Britain, under a common Parliament. Scotland’s territory and by extension that of the UK, was subsequently extended to comprise Rockall in 1956, while Section 126 of the Scotland Act 1998 defines Scotland as including the UK’s internal waters and territorial sea as are adjacent to Scotland. In 2022, the UK Supreme Court ruled that the Scottish Parliament lacked unilateral power to legislate for a Scottish independence referendum. However, the decision did not make Scottish independence impossible, it established that Westminster authorisation was legally required before the devolved Parliament could set in motion such a referendum (Torrance, 2026).

The Crown of Ireland Act 1542 established the title, King of Ireland. The 1800 Acts of Union consolidated Great Britain and Ireland as the United Kingdom of Great Britain and Ireland. The 1920 Government of Ireland Act provided for the constitutional division of Ireland thereby creating two autonomous jurisdictions, Southern Ireland and Northern Ireland. Under the terms of the 1922 Anglo-Irish Treaty, the Irish Free State was created leaving Northern Ireland within the UK and with legislation later recognising the independence of the Republic of Ireland (Torrance, 2026). 

On 7 December 1922, Northern Ireland’s Parliament voted in favor of remaining as part of the UK, thereby creating the principle of consent. The UK Parliament equally passed the 1927 Royal and Parliamentary Titles Act that changed the name of the Parliament of the United Kingdom of Great Britain and Ireland to the Parliament of the United Kingdom of Great Britain and Northern Ireland. Northern Ireland’s Parliament was prorogued in 1972 and abolished in 1973 (Torrance, 2026). Moreover, the 10 April 1998 Good Friday Agreement/ Belfast Agreement, acknowledges Northern Ireland’s continued membership in the UK while offering a democratic means to modify its constitutional status (Santos, 2026). 

On this basis, the UK has never been a fully centralised unitary state. Instead, it is a constitutional vessel crafted from distinct unions and successive constitutional settlements with its legal framework holding the constituent nations together notwithstanding the divergence of their political trajectories.

The Brexit Card

The 2016 Brexit referendum unveiled diverging views across the UK hence the major political schism and the deepening Union’s constitutional fractures. With a clear majority in Scotland and Northern Ireland voting to remain, 62.0% and 55.8%, nationalists called into question the UK’s decision to leave the EU. Wales with a narrow majority, (52.5%), however voted in favour of leaving the EU despite regional differences and a solid backing from Cardiff to remain (Paun & Isaac, 2026). 

Whereas Brexit promised to take back control, it ended up conflicting with the UK’s constitutional structure, one sovereign Parliament and three devolved legislatures. With devolution having been shaped by EU rules, Brexit raised concerns over the consequences of regulatory and economic divergence as legislative authority over key policy areas returned from Brussels to Westminster. In addition, while Theresa May’s government opened discussions to implement a framework of cooperation between the four administrations, Boris Johnson’s government opted for muscular unionism. The United Kingdom Internal Market Act 2020, also identified as Westminster’s power grab by Cardiff and Edinburgh, disregarded devolved authority (Paun & Isaac, 2026). It neglected the Sewel Convention, a principle restricting Westminster from adopting legislation matters falling within devolved competence without approval by the devolved legislatures (Paun & Isaac, 2026; Nyatanga, 2026), Senedd, Scottish Parliament, and Northern Ireland Assembly. Even so, the action was not isolated. For one, five Brexit-affiliated bills were implemented without approval of devolved governments during the period 2018-2023, inclusive of the EU Withdrawal Act 2018 passed despite objections by the Scottish Parliament (Paun & Isaac, 2026).

In Northern Ireland, divisions deepened between pro-EU and Brexit supporters. Boris Johnson opted for a barrier to east-west trade, through a new border in the Irish Sea. The UK government experienced a substantial erosion of public confidence, while the implementation of the new arrangements played a significant role in the continued failure of power-sharing and devolved governance in Northern Ireland between February 2022 and February 2024. The executive was however restored following the commitment by Rishi Sunak’s government to reduce disparities and promote east-west trade (Paun & Isaac, 2026). 

Brexit can therefore be viewed as a contributing factor in the continuing disintegration of the Union given the centralisation of power in Westminster as well as the declining public legitimacy of devolved governments, given the approval of key legislation without their consent. This has contributed to a growing perception in Edinburgh, Cardiff, and Belfast that Westminster has turned a blind eye to devolved governance, amplifying nationalist rhetoric that increasing autonomy or reunification in the case of Northern Ireland, would promote democratic accountability and oversight.

Final Reflection

Following the unilateral demarcation of territorial boundaries in foreign jurisdictions, Britain now realises that its constitutional map is subject to change. Britain no longer has any imperial possessions, economic advantage, and military influence which once set the foundation of its global power. Furthermore, the UK constitutional framework contains an inherent tension. Westminster continues to exercise legal authority as the Union’s democratic legitimacy relies, in part, on the consent of its constituent nations. In this case, the law provides the machinery while consent provides the fuel. While the constitutional order remains operational despite public skepticism in the political system, internal cohesion and stability might be short-lived. The potential breakup thus transcends competing views of national identity, boundaries and political stability. It is a question of political power, who holds the decision-making authority, and how legitimacy can be sustained when constituent nations no longer share a common political future.

References 

Government of Wales Act 2006, c. 32, sch. 7A, pt. 1, para. 1(b). (2006). https://www.legislation.gov.uk/ukpga/2006/32/schedule/7A/part/1 

Nyatanga, D. (2026, April 21). Sewel, elections and the future of the devolution settlement. The Constitution Society. https://consoc.org.uk/sewel-elections-future-devolution/  

Paun, A., Hall, D., & Isaac, M. (2026, May 15). Welsh independence. Institute for Government. https://www.instituteforgovernment.org.uk/explainer/welsh-independence

Paun, A., & Isaac, M. (2026, June 19). Brexit at 10: Devolution. Institute for Government.  https://www.instituteforgovernment.org.uk/comment/brexit-10-devolution 

Santos, E. A. (2026, September 18). The Good Friday Agreement (1998): The principle of consent and Northern Ireland’s constitutional status. Diplomacy and Law. https://www.diplomacyandlaw.com/post/the-good-friday-agreement-1998

Torrance, D. (2026, May 8). The United Kingdom and independence. House of Commons Library. https://commonslibrary.parliament.uk/research-briefings/cbp-10649/ 

Vote Wales. (2026, February 18). What is the Senedd? https://vote.wales/about-the-senedd/what-is-the-senedd/

Wales Act 2017: Explanatory notes. (2017). legislation.gov.uk. https://www.legislation.gov.uk/ukpga/2017/4/notes/division/6/index.htm 

Welsh Government. (2026, February 2). Cabinet handbook—Section 6: Legislation and the law. https://www.gov.wales/cabinet-handbook-section-6-html