Constitutional Law: Devolution

Devolution in the United Kingdom

There are mainly three constitutional structures across the world:

  • Unitary: the country’s central government and legislature runs the entire territory.
  • Federal: power is divided between a central government and legislature and state governments and legislatures. The division of power is regulated by a written constitution.
  • Devolution: devolution is a half-way house between these models. The country is mainly run by a central government, with power ‘devolved’ to smaller authorities and legislatures within the territory by statute.

The UK is has a devolution structure. There is a central government and Parliament. That central system then devolves some executive and legislative functions to the governments and legislatures of Northern Ireland (Northern Ireland Act 1998), Scotland (Scotland Act 1998), and Wales (Government of Wales Act 1998). Power is not devolved equally to each nation, however.

Northern Ireland

The Northern Ireland Act establishes the Northern Ireland Assembly and Executive. To account for the nation’s unique history, it involves an unusual power-sharing arrangement.

The Shared Executive

The Northern Ireland Executive Committee is headed by a First Minister and Deputy First Minister, each from different parties according to their electoral support. These then choose the remaining Ministers together.

Breakdown of Devolution

If the First Minister resigns or leaves office, so too must the Deputy – and vice versa. This happened between 2017-2020 when relations soured between the Democratic Unionist Party and Sinn Féin parties. Essential administration was taken over by UK civil servants. Some government functions could not be carried out at all, however, such as where statute specified the function can only be performed by a Minister: Re Judicial Review (Buick)[2018] NIQB 43.

The Assembly

The Assembly consists of 108 Members, six from each constituency. They can make any law unless: the subject matter is extra-territorial, conflicts with ECHR rights, is religiously or politically discriminatory, modifies an entrenched law (such as the Human Rights Act 1998) or is an exempted matter: Northern Ireland Act 1998, s.6(1). References can be made to the Supreme Court to determine if a Bill falls outside of the Assembly’s competence: s.11.

s.5 of the Northern Ireland Act 1998 retains the UK Parliament’s power to make law for Northern Ireland. However, the Assembly has the power to amend Acts of Parliament insofar as they relate to Northern Ireland.

Under the non-legal ‘Sewel Convention’, the UK Parliament does not tend to legislate for Northern Ireland without obtaining a ‘Legislative Consent Motion’. This is an indication from the devolved legislature that it is happy to let Parliament make the relevant legislation.


The Scotland Act 1998 regulates the Scottish Parliament and its executive, known as the Scottish Government. Both are permanent parts of the constitution, which can only be abolished with the Scottish populace’s consent.

The Executive

The Scottish Government is run by the First Minister, those Ministers appointed by them, the Lord Advocate and the Solicitor-General. They are accountable to both the Scottish Parliament and its courts.

The Scottish Parliament

The Scottish Parliament consists of 129 seats. Most Members are elected using the first-past-the-post, constituency-linked system, but there is a supplemental ‘additional members’ system. The additional members are chosen from party lists.

Legislative Competency

The Parliament can make any law for Scotland unless: the subject matter is extra-territorial, a reserved matter (defined in Schedule 5), incompatible with the ECHR, affects the judicial status of the Lord Advocate, or involves modification of entrenched statutes: s.29, Scotland Act 1998.

Judicial Oversight

The UK courts can review Scottish legislation and executive action to ensure it falls within their competence. Ultimate jurisdiction rests with the UK Supreme Court. For guidance on how the courts approach Scottish legislation, se Imperial Tobacco v Lord Advocate [2012] UKSC 61.

The UK Parliament retains the power to make law for Scotland under s.28(7) of the Scotland Act 1998. However, the Sewell Convention also applies to Scotland, where it is codified under s.28(8).


Devolution in Wales is not as extensive as Scotland or Northern Ireland. Nevertheless, the Government of Wales Act 1998 regulates the Welsh legislative assembly (the Senedd) and government.

The Senedd

The Senedd comprises of 60 Members, elected using the additional member system of voting.

Legislative Competence

Originally, the Senedd could only legislate on a set list of matters. They now have the power to make laws on any non-reserved matter, but the list of reserved matters is far more extensive than under the Scottish and Northern Irish arrangements: see  Wales Act 2017. They can only pass subordinate legislation and cannot modify Acts of Parliament affecting Wales. Despite this, the Sewell Convention also applies to Wales.

The Executive

The Welsh Government is led by a First Minister who appoints other Ministers from Senedd members. The First Minister is nominated by the Senedd.

Disputes about executive or legislative competence in Wales can be referred to the courts for resolution.

The West Lothian Question

England does not have a devolved legislature or executive. The result is that Scottish, Welsh and Northern Irish MPs in the central Parliament are capable of voting on legislation which affects England, but English MPs cannot vote on matters which affect the other nations in the devolved parliaments. This is controversial, and the debate is known as the ‘West Lothian Question’.