The Nature of the UK Constitution

This lesson examines the distinctive nature of the UK constitution — one of only a handful of constitutions worldwide that is uncodified, unentrenched, and built on an evolving blend of statute, convention, and common law. Understanding the UK constitution is fundamental to A-Level Politics because every question about power, rights, and governance in Britain ultimately traces back to constitutional principles.

What Is a Constitution?

A constitution is a set of rules, laws, and practices that:

Establish the institutions of government (Parliament, the Executive, the Judiciary).
Define the relationship between these institutions and between the state and the individual.
Limit the powers of government and protect the rights of citizens.

Constitutions may be codified (written in a single authoritative document, e.g. the US Constitution of 1787) or uncodified (drawn from a range of sources, as in the UK). The distinction is not simply about being written versus unwritten — much of the UK constitution is in fact written down, but it is not contained in one single document with higher legal status.

Key Features of the UK Constitution

1. Uncodified

The UK constitution is not contained in a single document. Instead, it is found across many different sources: Acts of Parliament, court rulings, conventions, authoritative texts, and (historically) EU law. This means there is no single piece of paper one can point to and say: "This is Britain's constitution."

Advantages of an uncodified constitution:

Flexibility — it can evolve organically without formal amendment procedures.
It reflects the pragmatic, evolutionary nature of British political history.
Parliament retains sovereignty; no constitutional court can override the legislature.

Disadvantages:

Uncertainty — not all rules are clearly defined or accessible.
Weak protection of rights — Parliament can change constitutional rules with a simple majority.
Lack of public awareness — citizens may not know what the constitution says.

2. Unentrenched

A constitution is entrenched when it is protected by special amendment procedures (e.g. a two-thirds supermajority or a referendum). The UK constitution is not entrenched — any law forming part of it can be repealed or amended by a simple Act of Parliament passed by a bare majority. For example, the Fixed-term Parliaments Act 2011 was passed by ordinary legislation and was later repealed in 2022 by the Dissolution and Calling of Parliament Act 2022.

Exam Tip: Be precise — say unentrenched rather than flexible. All constitutions can be changed; the question is how difficult it is to change them.

3. Unitary (Traditionally)

The UK has traditionally been a unitary state, meaning sovereignty resides at the centre — in the Westminster Parliament. Power may be delegated to devolved bodies (the Scottish Parliament, Senedd Cymru, the Northern Ireland Assembly), but Westminster retains the legal authority to overrule or abolish them. This contrasts with federal systems (e.g. the USA, Germany) where power is constitutionally divided between central and regional governments.

However, the reality since 1998 is more complex. Devolution has created what some commentators call a quasi-federal arrangement, since in practice Westminster is unlikely to legislate on devolved matters without the consent of the devolved legislatures (the Sewel Convention).

4. Parliamentary Sovereignty as the Core Principle

Parliamentary sovereignty, as described by A.V. Dicey, holds that:

Parliament can make or unmake any law.
No body can override or set aside an Act of Parliament.
No Parliament can bind its successors.

This means there is no higher law against which Acts of Parliament can be tested and struck down — unlike the USA, where the Supreme Court can declare legislation unconstitutional.

5. Based on Fusion of Powers

Unlike the USA's separation of powers, the UK system involves a fusion of powers: the Executive (the Prime Minister and Cabinet) is drawn from and sits in the Legislature (Parliament). The PM must command a majority in the House of Commons. This means that the Executive typically dominates the Legislature, raising important questions about accountability and the balance of power.

Historical Development

The UK constitution has evolved over centuries, shaped by key events and documents:

Date	Event/Document	Significance
1215	Magna Carta	Established the principle that the monarch is subject to law
1689	Bill of Rights	Affirmed parliamentary supremacy over the Crown
1701	Act of Settlement	Secured Protestant succession and judicial independence
1707	Acts of Union	United England and Scotland under one Parliament
1911 & 1949	Parliament Acts	Reduced the power of the House of Lords
1972	European Communities Act	Incorporated EU law into UK law (repealed 2020)
1998	Human Rights Act	Incorporated the European Convention on Human Rights into UK law
1998	Scotland Act / Government of Wales Act / Northern Ireland Act	Established devolved legislatures

Codified vs Uncodified: A Spectrum

It is a mistake to see constitutions as either purely codified or purely uncodified. In practice, constitutions sit on a spectrum:

The USA has a codified constitution, but much of its practical operation depends on conventions, judicial interpretation, and executive orders.
The UK has an uncodified constitution, but significant parts are written in statutes (e.g. the Human Rights Act 1998, the Scotland Act 1998).

The real question is whether the UK's sources have higher law status — and they do not. Parliament can amend them by ordinary legislation.

Case Studies

Case Study 1: The Prorogation Crisis (2019)

In September 2019, Prime Minister Boris Johnson advised the Queen to prorogue (suspend) Parliament for five weeks during a critical period of Brexit negotiations. The Supreme Court, in R (Miller) v The Prime Minister [2019], unanimously ruled the prorogation unlawful, stating it had the effect of frustrating Parliament's ability to carry out its constitutional functions. This case demonstrated:

The power of the judiciary to review the Executive's use of the prerogative.
The tension between an uncodified constitution and the rule of law.
The argument that key constitutional principles (such as parliamentary sovereignty and executive accountability) exist even without a codified document.

Case Study 2: The Human Rights Act 1998

The HRA incorporated the European Convention on Human Rights (ECHR) into UK domestic law. Before the HRA, citizens had to take cases to the European Court of Human Rights in Strasbourg. The HRA allows UK courts to issue declarations of incompatibility (under Section 4) but cannot strike down Acts of Parliament, preserving parliamentary sovereignty. The Act has been controversial — some argue it empowers unelected judges, while others see it as essential rights protection.

Evaluation: Strengths and Weaknesses of the UK Constitution

Strengths	Weaknesses
Flexible — adapts to changing circumstances	Uncertain — unclear rules can be exploited
Evolutionary — reflects British political culture	Executive dominance — the government controls the legislature
Pragmatic — avoids rigidity	Weak rights protection — no entrenched Bill of Rights
Democratic — Parliament is sovereign	Centralisation — power concentrated at Westminster

Key Debates

Should the UK adopt a codified constitution? — This is one of the most common exam questions. You must present arguments on both sides and reach a justified conclusion.
Has parliamentary sovereignty been eroded? — By the EU (pre-Brexit), devolution, the HRA, and judicial review.
Is the UK still a unitary state? — Or has devolution created a quasi-federal system?

Summary

The UK constitution is uncodified, unentrenched, and traditionally unitary.
It is based on parliamentary sovereignty and a fusion of powers.
It has evolved over centuries through statutes, conventions, and landmark events.
The Miller case (2019) and the HRA (1998) illustrate how the constitution operates in practice.
Key debates focus on codification, parliamentary sovereignty, and the impact of devolution and rights legislation.

Exam Tip: Always use specific examples and case studies to support your arguments. Generic statements about the constitution will not achieve top marks.