The territorial constitution: what is it and why does it matter?

Summary

• The United Kingdom’s territorial constitution has evolved over time. Major changes occurred in the 1990s, with the creation of devolved legislatures and governments in Scotland, Wales and Northern Ireland.

• The territorial constitution seeks to accommodate various nations, regions and identities in a single state, and to devolve power closer to those being governed. But it also works within the UK’s core constitutional doctrine of parliamentary sovereignty – meaning that the UK parliament remains constitutionally supreme.  

• This can lead to tensions over the practical operation of devolution, especially relating to the balance between central and devolved power. England also lacks comparable representation to the UK’s other constituent parts.  

Background

The UK comprises four constituent parts – England, Scotland, Wales and Northern Ireland – bound together in the ‘Union’. In addition to the Westminster parliament and government, parliaments and governments exist in Scotland, Wales and Northern Ireland (but with no equivalent England-wide body). There are also systems of local government across the UK.

This briefing focuses on the structure of the Union. There are a number of unique aspects to the territorial constitution as it operates in Northern Ireland, which are discussed at greater length in our briefing ‘How does politics work in Northern Ireland?’.

How did the territorial constitution evolve?

Wales was ruled by English kings from the late 13th century, with legal unification taking place over a period of time. The Scottish and English crowns were held by the same monarch from 1603, with the Acts of Union forming Great Britain in 1707. English monarchs exerted significant control in Ireland from the 12th century onwards, and the United Kingdom of Great Britain and Ireland was formed in 1801; Northern Ireland was created in 1921, and opted to remain a devolved part of the UK state following the 1921 Anglo-Irish Treaty. 

Various systems of administrative devolution applied in different places and at different times, but the current system of political devolution to Scotland, Wales and Northern Ireland dates from the late 1990s. Referendums in 1997 in Scotland and Wales approved the creation of a devolved representative body in each country. The Scottish Parliament and National Assembly for Wales were duly established, and powers devolved via legislation. The National Assembly for Wales initially lacked primary legislative powers, but these were granted in 2006; in 2020 it was renamed the Welsh Parliament/Senedd Cymru. 

What principles underpin the territorial constitution?

The UK combines various nations and regions in a single state. This means that its citizens may hold multiple identities, being English, Scottish, Welsh or Irish, Northern Irish or Ulster in addition to, or instead of, British. Likewise, different identities hold different levels of importance for different people. A 2024 survey found that 23% of people in England felt exclusively or primarily English, 45% equally English and British, and 22% exclusively or primarily British. In Scotland, 57% of respondents reported feeling exclusively or primarily Scottish, 25% equally Scottish and British, and 12% exclusively or primarily British. 

The territorial constitution allows multiple identities and interests to co-exist within the state, as well as allowing for power to be devolved closer to those governed. But it also operates within the UK’s system of parliamentary sovereignty, in which the UK parliament is constitutionally supreme. This can result in tension between those who have sought to increase central influence over devolved areas (sometimes referred to as ‘muscular unionists’), and those who support greater decentralisation.

How does devolution work?

Devolution refers to the granting of powers from the UK parliament and government to the legislatures and governments of the nations and regions of the UK. UK devolution is asymmetrical – different policy areas and powers are devolved to each of Scotland, Wales and Northern Ireland, while England has a system of limited sub-national devolution to regional mayors. Some policy areas, such as defence, the constitution, and most economic policy, rest with Westminster as ‘reserved’ powers. In addition to reserved policy areas, Westminster formally retains three key powers:

• To block devolved legislation which the UK government believes would: contravene the UK’s international obligations; risk compromising national defence; or modify the law on reserved matters with ‘adverse effect’. In 2023, the UK government used this power to block Scottish legislation on gender recognition.
• To legislate in devolved policy areas. This is not always controversial: there may be good reasons why it suits all parties for Westminster to legislate, especially where policy goals are shared. The power is governed by the Sewel convention, which says that the UK government will not ‘normally’ seek to legislate in devolved policy areas without the consent of the relevant parliament – but, as confirmed by the Supreme Court in 2017, the convention is non-binding.
• To alter the devolution settlement, by amending the primary legislation in which it is set out – though any move to restrict the devolution settlements would in practice be highly controversial.

This is a crucial distinction from federal systems (such as Australia, Canada, Germany and the United States), where the existence and powers of sub-national states are included in the constitution. The federal units are generally represented in the legislature, often in the second chamber.

What are the key tensions in the UK’s territorial constitution?

1. Intergovernmental relations

• Devolution allows for governments of different parties to be formed in different parts of the UK. This means that smooth relationships between the UK and devolved administrations often require cross-party working of a type which is relatively unusual at Westminster. The system for intergovernmental relations aims to provide an environment where competing priorities and viewpoints can be constructively aired and disputes resolved.
• Intergovernmental relations once operated largely informally, through the Joint Ministerial Committee (which brought together the leaders of the UK, Scottish, Welsh and Northern Ireland governments on a generally ad hoc basis). A new system was introduced in 2022, consisting of three tiers: policy-specific interministerial groups, an interministerial standing committee, and the Prime Minister and Heads of Devolved Government Council. This structure was supplemented in 2024 by the Council of Nations and Regions, which brings together the Prime Minister, heads of devolved governments, and English mayors.
• Another key aspect of intergovernmental relations is the approach taken to the UK’s post-Brexit internal market (i.e. the movement of goods and services between its constituent parts). The UK Internal Market Act 2020 has been criticised for constraining the devolved nations’ ability to regulate. A more consensual approach can be taken through the use of Common Frameworks: sector-specific agreements between the UK and devolved governments.

2. Sewel convention and legislating in devolved areas

• As noted above, the Sewel convention sets out that the UK parliament will not ‘normally’ legislate on devolved topics without the consent of the relevant devolved legislature. But the convention is non-binding, and there have been tensions over its operation.
• The system generally operated smoothly until the Brexit process began. Between 2016 and the UK’s exit from the European Union, several Acts were passed without consent from at least one relevant party; more have followed. This has led some to call for the Sewel convention to be substantially strengthened. More incremental improvements have also been suggested (for example, the earlier sharing of draft legislative texts). Debates about when the Sewel convention should apply also show ambiguities about the boundaries of devolved competence. In its 2024 general election manifesto, Labour promised a new Memorandum of Understanding on the operation of the Sewel convention, which could provide an opportunity for such clarification.

3. Money

• Scotland, Wales and Northern Ireland all have some devolved fiscal powers (with the extent of the powers held varying significantly between the three). The other key element of the financial settlement is funding provided by the UK government, mainly in the form of a ‘block grant’.
• The block grant is based on historical spending decisions. Changes to it are calculated according to the Barnett formula, under which the grant varies in proportion to changes to spending on relevant government services in England. The block grant is not ring-fenced by service. The formula dates from the 1970s and has never been replaced, though it has been periodically updated, significantly through the introduction of a spending ‘floor’ for Wales and Northern Ireland. There have been calls to update it, particularly to use a ‘need-based’ formula.
• Total public spending per head is generally greater in Scotland, Wales and Northern Ireland than in England. Some argue this reflects relative GDP levels, and the costs of providing services to more dispersed populations. Others claim that it underserves English regions with similar needs.

4. English representation

• Under current arrangements, England is the only nation of the UK without its own parliament and government, and there is no distinct all-England voice in intergovernmental relations. Matters affecting only England are decided at Westminster, with MPs representing non-English constituencies able to vote on them. This potentially allows England-only policy to pass on the votes of MPs representing constituencies outside England. A system of ‘English Votes for English Laws’ was introduced in 2015, but led to little additional scrutiny, and was scrapped in 2021.

What is the future of the Union?

The UK has long been described as a voluntary union. Independence movements exist in Scotland and Wales, and a recent commission in Wales considered three options for the country’s future: enhanced devolution, federalism within the UK, and independence. Independence referendums can take place only with the UK government’s agreement (as confirmed by the Supreme Court in 2022), but there are no agreed rules as to when a referendum might be called, or how it might be conducted. An independence referendum in Scotland was granted, and held in 2014, but two subsequent requests by the Scottish National Party were refused by then Prime Minister Boris Johnson. 

A significant minority in Northern Ireland support Irish unification. The circumstances under which a referendum would need to be held are laid out in the Belfast/Good Friday Agreement and the Northern Ireland Act 1998, as discussed in the Northern Ireland briefing in this series.

A further question concerns England’s lack of distinct representation via a devolved legislature, or dedicated minister. There have been calls at times for an English parliament, but there would be major questions to be answered about the powers and composition of any such body. Successive governments have instead sought to increase the powers devolved to English regions.

Finally, some have called for moves toward full federalism, including recently the Independent Commission on the UK’s Future chaired by Gordon Brown. Any such move would entail ending the UK’s core constitutional principle of parliamentary sovereignty. It would also need to confront the disparity between the sizes of the UK’s constituent parts, and find a way to preserve fair representation without creating a single dominant entity. England has 84% of the UK’s population: far more than the largest entity in existing federal systems. New South Wales has 31% of Australia’s population, Ontario 39% of Canadians, and North Rhine-Westphalia 21% of Germans. An alternative would be for England’s regions to be represented in a federal system; but evidence suggests that many English regional identities are not strongly held, and there is no serious suggestion that the regions might be given similar fiscal and legislative powers to Scotland, Wales and Northern Ireland.

Any move toward a fundamental change in the composition of the UK would require significant work, which has not yet been done. But reforms could be made to help the existing arrangements work better. Those who do not want to see independence, or continuing conflict, have a responsibility to make the existing system work as well as possible.

About the authors

Lisa James is a Senior Research Fellow at the Constitution Unit.

Meg Russell is Professor of British and Comparative Politics at UCL and Director of the Constitution Unit.

Alan Renwick is Professor of Democratic Politics at UCL and Deputy Director of the Constitution Unit.