The UK constitution: its nature as uncodified and unentrenched, its sources, the doctrines of parliamentary sovereignty and the rule of law, and debates about reform.

What this dot point is asking

This WJEC AS topic asks you to explain the nature, sources and underlying principles of the UK constitution and to evaluate whether it should be reformed. You need to understand why the UK constitution is unusual (uncodified and flexible), where its rules come from, and the two doctrines that hold it together, parliamentary sovereignty and the rule of law.

The answer

What a constitution is and the nature of the UK's

The UK constitution has three defining features. It is uncodified: unlike the United States, the UK has no single written constitutional document, so its rules are scattered across many sources. It is unentrenched (flexible): there is no special amendment procedure, so a constitutional change can be made by an ordinary Act of Parliament passed by a simple majority. And it is unitary: legal sovereignty is held by the central Parliament at Westminster, even though power has been devolved to Wales, Scotland and Northern Ireland.

The sources of the constitution

The UK constitution draws on five main sources.

• Statute law. Acts of Parliament are the highest source. Examples with constitutional importance include the Human Rights Act 1998, the Government of Wales Acts 1998 and 2006, and the European Union (Withdrawal) Act 2018.
• Common law. Law developed by judges through precedent, together with the royal prerogative (historic powers of the Crown now exercised by ministers, such as deploying the armed forces).
• Conventions. Long-established but non-legal rules that are followed in practice, such as the monarch always granting royal assent and the Prime Minister being a member of the House of Commons.
• Authoritative works. Respected texts that are used as guides to constitutional practice, such as A. V. Dicey's writing on the constitution and Erskine May on parliamentary procedure.
• European Union law. While the UK was a member, EU law took precedence over conflicting domestic law; most of this was repealed following Brexit, illustrating the flexibility of an uncodified system.

The two key doctrines

These doctrines can pull against each other. The rule of law implies legal limits on government, yet parliamentary sovereignty means Parliament can in theory pass any law it wishes. In practice the tension is managed by conventions, political accountability and judicial review of how powers are exercised.

The debate about reform

The central reform question is whether the UK should adopt a codified constitution. Supporters argue it would protect rights, clarify the rules and limit an over-powerful executive. Opponents argue that flexibility is a strength, that the uncodified system has delivered stability, and that codification would hand power to unelected judges. Reforms since 1997 (devolution, the Human Rights Act, the creation of the Supreme Court) have changed the constitution significantly without codifying it.

Examples in context

Flexibility in action. Devolution shows how readily the uncodified constitution can change. The Government of Wales Act 1998 created the National Assembly with limited powers; the 2006 Act and later changes expanded them; and the Senedd and Elections (Wales) Act 2020 renamed the body the Senedd and lowered the voting age to 16. Each step was an ordinary Act of Parliament, requiring no special amendment procedure, something that would be far slower under an entrenched constitution.

Try this

Q1. Name three sources of the UK constitution. [3 marks]

• Cue. Any three of statute law, common law, conventions, authoritative works, and (historically) EU law.

Q2. What does parliamentary sovereignty mean? [4 marks]

• Cue. Parliament is the supreme legal authority; it can make or unmake any law; no Parliament can bind its successor; the courts cannot overturn an Act.

Q3. To what extent should the UK adopt a codified constitution? [25 marks]

• What the marker wants. A balanced evaluation weighing entrenched rights and clarity against flexibility and democratic accountability, ending in a supported judgement.