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How power is exercised within the UK

The starting point for understanding Wales’ constitutional arrangements is to understand how power is divided and shared within the UK. Historically all power in the UK vested in the Crown, the doctrine of the divine right of kings providing royal and political legitimacy to rule directly from the will of God - the Monarch being sovereign, holding supreme authority. Over the centuries, however, the Monarch’s power has been divided, shared and limited in a number of ways.

This process began most notably (in relation to England) with the Magna Carta in the 13th century which limited the power of the Monarch, and the Bill of Rights of 1688 which established certain rights of the (English) Parliament. Most significant was the development of the concept of ‘Parliamentary sovereignty’. In simple terms this provides that:

  • Parliament can pass laws about any matter,
  • no Parliament can bind a future Parliament (in other words a future Parliament may always change the law), and
  • a law passed by Parliament cannot be struck down by the courts (because there is no ‘higher’ constitutional law against which an Act of Parliament can be judged).

The absence of a written or codified constitution also means that there are no limits to the power of Parliament and no requirements for it to act in a particular way.

The UK Parliament makes laws by passing Acts of Parliament (also known as primary legislation). As well as changing the law by way of the Act itself, Acts of Parliament may also confer power on others to change the law. This includes conferring power on the devolved legislatures (Senedd Cymru, the Scottish Parliament and the Northern Ireland Assembly) to make their own forms of primary legislation, and conferring more limited power on Ministers to make ‘subordinate legislation’, normally by way of ‘statutory instrument’.

Although the concept of Parliamentary sovereignty still applies, many consider that Parliament’s supremacy has either in law or in practice become limited in recent years. The limitations arise from entering into international obligations (membership of the European Union and complying with the European Convention on Human Rights) and through recognition of the will of the people of the historic nations of the UK (devolution of power to new legislatures).

Dividing power between legislatures within the UK, and conferring law making and other powers on Ministers, has also seen the development of an enhanced role for the courts, which now more often play a role in adjudging where power lies and whether it has been exercised correctly. 

Devolution of power to Wales

The Government of Wales Act 2006 (GoWA 2006) established a newly constituted National Assembly for Wales as a fully-fledged legislature, and a separate executive initially named the ‘Welsh Assembly Government’ and later changed to simply the ‘Welsh Government’. Significantly GoWA 2006 gave the (then) National Assembly power to pass its own primary legislation – initially by ‘Assembly Measure’ under a system by which limited competence was conferred (either by a Legislative Competence Order or by an Act of Parliament) on a piecemeal basis – and following the referendum on further law making powers in 2011 by ‘Assembly Act’ on any matter conferred by Schedule 7 to the Act. The National Assembly was renamed Senedd Cymru in May 2020, and Acts are now 'Senedd Acts'.

Since the coming into force of the Wales Act 2017, the extent of Senedd Cymru’s competence to legislate is defined in sections 108A and 109 of, and Schedules 7A and 7B to, GoWA 2006, which together set the parameters of legislative competence by reference to what the Senedd cannot do i.e. by listing matters that are reserved to the UK Parliament. 

Although the doctrine of Parliamentary sovereignty means that the UK Parliament may also legislate on matters that are not reserved to it (as well as on anything else), by convention (often referred to as the ‘Sewel Convention’) it will not normally do so except with the agreement of the National Assembly. The Scotland Act 2016 and the Wales Act 2017 made provision reflecting this convention in law and introduced the notion of the permanence of the Scottish Parliament and Scottish Government and the Senedd and the Welsh Government, respectively.  Whilst this suggests that the Parliamentary sovereignty of the UK Parliament has been limited as a result of devolution, the Supreme Court held in the case of Miller, that the Sewel provisions are non-justiciable, but that the Sewel Convention is nevertheless an important constitutional convention, which plays a "fundamental role in the operation of our constitution".

Like Acts of Parliament, Senedd Acts often confer powers on Ministers to make subordinate legislation, generally by statutory instrument. Senedd Acts also often confer powers on the Welsh Ministers (or other bodies) to issue guidance or codes of practice.  Such ‘soft law’ is not legally binding but those to whom it is directed are required to take it into account.

European law

European law also impacts upon the power of Parliament, as well as on the powers of Ministers and the legislatures in Wales, Scotland and Northern Ireland. During the time the United Kingdom was a Member State of the European Union (EU) the laws of the EU were incorporated into UK law (see section 2 of the European Communities Act 1972).

Case law of the European Court of Justice has established that the UK’s membership of the European Union meant that where there is a conflict between European law and domestic laws made in the UK, European law prevails. This principle was confirmed by the UK courts in the case of R v Secretary of State for Transport, ex parte Factortame (No. 2) [1990] 3 WLR 818, in which it was held that:

“If the supremacy within the European Community of Community Law over the national law of member states was not always inherent in the EEC Treaty it was certainly well established in the jurisprudence of the Court of Justice long before the United Kingdom joined the Community. Thus, whatever limitation of its sovereignty Parliament accepted when it enacted the European Communities Act 1972 was entirely voluntary. Under the terms of the 1972 Act it has always been clear that it was the duty of a United Kingdom court, when delivering final judgment, to override any rule of national law found to be in conflict with any directly enforceable rule of Community law.”

The EU institutions (the European Commission, the Council of Europe and the European Parliament) can only legislate on those areas that the various Member States have agreed come within the remit of the EU. Therefore, if a policy area is not referred to in the Treaty on the Functioning of the European Union or one of the various other EU treaties, the EU cannot legislate on it. Nevertheless, the scope of EU laws is wide-ranging, covering areas such as economic matters, agriculture, the environment, energy, employment and competition. Some European law is automatically applicable in the UK, including treaty provisions and EU Regulations. 

Other European law (such as EU Directives) is not automatically applicable, but the UK is legally obliged to implement it into domestic law.

By virtue of sections 80 and 108A of the Government of Wales Act 2006 laws made in Wales (whilst the UK was a Member state) must have been made in compliance with European law.


Human rights

The Human Rights Act 1998 gave “further effect to rights and freedoms guaranteed under the European Convention on Human Rights” and has had a significant influence on both the content and interpretation of UK law. Although the UK Parliament is not itself required to make laws in compliance with the convention rights, any Member of Parliament promoting a bill that does not comply must make a statement to that effect (which is a significant practical constraint on the freedom of Parliament to legislate as it wishes).

By virtue of sections 81 and 108A of the Government of Wales Act 2006 laws made in Wales must be made in compliance with the convention rights.

More information on the impact which the Human Rights Act 1998 has on our legal system can be found on the Introduction to Human Rights law page.

Common law and the laws of equity

The UK has a common law legal system. This means that in addition to statute law (laws made by the UK’s Parliaments and the Northern Ierland Assembly) it has a body of law that evolves over time as it is ‘declared’ by judges when they decide legal proceedings in the courts. In order to find out what the common law is on a matter, it is necessary to study the judgments handed down in the courts (usually referred to as caselaw).

The doctrine of precedent helps to keep common law relatively coherent and predictable. Under the doctrine of precedent, a judge must normally follow earlier judgments on the same legal matter. Furthermore, a judge is required to follow an earlier judgment made by a higher court than the court in which he or she sits.

Historically there was a separate strand of ‘judge made’ law, known as the laws of equity, which was also developed through caselaw. However, the distinction between common law and the laws of equity is not often of practical significance today, and both sets of laws are administered alongside each other and thought of together as the common law of the UK.

There is not always a clear dividing line between common law and statute law. Statute law may relate to a matter for which there is no common law.  On the other hand, a statute may replace the common law in an area or supplement or vary the common law (in other words both statute law and common law may apply to any given situation).

Law made in Wales is either primary legislation or subordinate legislation. There is no unique body of Welsh common law. This is because England and Wales is a single legal jurisdiction, and when judges declare points of common law, they are determining the law for both England and Wales.

Published on
Last updated
18 August 2021