The changing constitution and reform

Week 12 draws together the whole Year 1 UK Constitutional Law course. The topic is not simply a list of reforms. It asks a more demanding question: how does an uncodified constitution change, and what limits, if any, govern that change? Durham students should treat this week as a synoptic revision point. It connects parliamentary sovereignty, constitutional statutes, the rule of law, separation of powers, prerogative powers, devolution, the Human Rights Act, conventions, common law rights, and political freedoms.

The United Kingdom constitution changes through several channels. Parliament enacts statutes of constitutional importance. The courts develop principles of legality, constitutional statutes, judicial review and institutional competence. Ministers use prerogative and statutory powers. Political actors observe, contest or disregard conventions. Referendums sometimes supply political authority, though not, without legislation, legal authority. Devolved institutions exercise constitutionally significant powers, but within statutory limits. Reform is therefore dispersed, episodic and often reactive.

The central tension is between flexibility and constitutional control. Diceyan orthodoxy presents Parliament as legally unlimited: if Parliament can make or unmake any law, constitutional reform is principally legislative. Yet the modern constitution no longer fits comfortably within a simple legislative-sovereignty model. Thoburn distinguished constitutional statutes from ordinary statutes for the purposes of implied repeal. Jackson exposed judicial unease about an entirely unlimited Parliament. Miller (No 1) insisted that prerogative power could not alter domestic law and rights without statutory authority. Miller (No 2) applied constitutional principles to the prorogation of Parliament itself. Privacy International and Evans demonstrate the courts’ resistance to executive attempts to insulate legality from judicial supervision.

This does not mean that the courts have replaced Parliament as sovereign. That conclusion is too crude and usually performs badly in examinations. The more accurate proposition is that constitutional reform now occurs in a constitution structured by multiple legal and political principles. Parliamentary legislation remains the primary method of major legal change, but legislation is interpreted against constitutional assumptions. Executive action is constrained by statute, legality and accountability. Devolution has created politically entrenched institutions, even though orthodox legal doctrine treats Westminster as legally capable of alteration. Human rights protection under the HRA creates a dialogue rather than a strike-down model. Brexit restored certain formal legislative competences while also illustrating the continuing power of courts and statutes to structure constitutional change.

The examination skill is to avoid a chronological essay. The question will usually ask whether reform has produced a new constitution, whether parliamentary sovereignty remains adequate, whether codification is desirable, or whether the courts have become too powerful. The best answers identify the mechanism of change, the constitutional principle engaged, the institution empowered or constrained, and the legal consequence. A first-class answer also distinguishes legal validity from political legitimacy. Many reforms are legally valid but constitutionally controversial; others are politically powerful but legally dependent on legislation. That distinction is the spine of this topic.

The United Kingdom has never possessed a single founding constitutional moment. Its constitution has developed through settlement, statute, political practice, institutional adaptation and judicial interpretation. The Bill of Rights 1689, the Acts of Union, the Parliament Acts, the European Communities Act 1972, the devolution statutes, the Human Rights Act 1998, the Constitutional Reform Act 2005, the European Union (Withdrawal) Act 2018 and the Dissolution and Calling of Parliament Act 2022 are not chapters in a codified text. They are constitutional landmarks in an accretive system.

The twentieth century began with reform of the relationship between the Commons and the Lords. The Parliament Act 1911, passed in the context of conflict over the People’s Budget, reduced the House of Lords’ veto to a delaying power for most public Bills and preserved special rules for money Bills. The Parliament Act 1949 further reduced that delaying power. The Life Peerages Act 1958 changed the composition and social character of the Lords, while the House of Lords Act 1999 removed most hereditary peers. These reforms reveal a recurring feature of the UK constitution: institutional change is often partial. The Lords was not replaced with an elected second chamber; it was altered incrementally.

After the Second World War, the growth of the administrative state and delegated legislation placed greater pressure on judicial review and parliamentary scrutiny. The post-war constitution was still presented through Diceyan language, but government increasingly operated through broad statutory powers, administrative discretion and party discipline. Parliamentary sovereignty remained formally intact, yet the practical balance of power moved towards the executive. This tension underlies modern reform debates: the question is not only what Parliament can do, but whether Parliament can control the government that usually commands its majority.

The European Communities Act 1972 introduced a more radical form of constitutional change. It gave effect to directly applicable and directly effective European Community law within domestic law. Factortame showed that domestic courts could disapply inconsistent Acts of Parliament within the statutory scheme created by the 1972 Act. That did not abolish sovereignty, but it transformed the ordinary operation of statutes while membership continued. Brexit later confirmed, in orthodox terms, that Parliament could repeal the 1972 Act, but Miller (No 1) also showed that such repeal could not be achieved by prerogative notification alone where domestic rights and law were affected.

The late 1990s brought the most concentrated programme of constitutional reform in modern British history. Devolution created legislatures and executives in Scotland, Wales and Northern Ireland. The Human Rights Act 1998 incorporated Convention rights through a distinctive domestic model: courts interpret legislation compatibly where possible, but cannot invalidate primary legislation; they may instead issue declarations of incompatibility. The House of Lords Act 1999 altered the second chamber. Freedom of information legislation and electoral reform in devolved and European contexts contributed to a wider public-law culture.

The Constitutional Reform Act 2005 then restructured the judicial branch. It modified the office of Lord Chancellor, created the Supreme Court of the United Kingdom, and placed judicial appointments on a new footing. The significance was not merely administrative. It made visible a separation of powers previously obscured by the Appellate Committee of the House of Lords sitting within Parliament and by the Lord Chancellor’s hybrid role.

The period after 2010 has been marked less by coherent constitutional design than by sharp constitutional contestation. The Fixed-term Parliaments Act 2011 attempted to regulate dissolution; it was later repealed. The Scottish independence referendum, the 2016 EU referendum, Brexit legislation, Miller (Nos 1 and 2), debates over judicial review, voter identification, retained EU law and the Northern Ireland arrangements all show a constitution under strain. Durham students should see the pattern: UK constitutional reform is frequently pragmatic, politically driven and legally mediated after the event. Its genius is adaptability; its weakness is the absence of settled rules about when major constitutional change requires special process, consensus or entrenchment.

The first principle is parliamentary sovereignty, but it must be stated with care. In orthodox form, Parliament may enact any law, and no person or body may set aside an Act of Parliament. That proposition remains central to the legal constitution. The Human Rights Act does not authorise courts to strike down Acts. Devolution legislation defines the competence of devolved institutions by statute. Brexit was effected through Acts of Parliament. Reform normally requires legislation, and legislation remains the most authoritative domestic legal form.

But sovereignty is no longer an adequate complete description of constitutional change. First, the courts distinguish certain statutes as constitutional, with consequences for implied repeal. Secondly, legislation may be legally valid while constitutionally improper, which introduces the difference between legal capacity and constitutional legitimacy. Thirdly, parliamentary sovereignty does not itself decide how executive power is controlled. Much modern constitutional litigation concerns whether ministers may act under prerogative or statutory powers, whether they have frustrated statutory purpose, or whether they have exceeded constitutional limits.

The second principle is the rule of law. In reform debates the rule of law performs several functions. It insists that government must act under legal authority. It supports access to courts and judicial review. It informs strong presumptions against ouster clauses and against interference with fundamental rights. It also requires legal certainty, publicity and institutional accountability. The Constitutional Reform Act 2005 expressly preserves the rule of law, though it does not codify its content. Bingham’s account remains a useful framework, but examination answers should connect it to cases. In Evans, a ministerial certificate could not be used so as to undermine the judicial decision-making scheme enacted by Parliament. In Privacy International, the Supreme Court read an ouster provision restrictively. In Miller (No 2), prorogation was unlawful because it frustrated Parliament’s constitutional functions without reasonable justification. These are rule-of-law decisions in institutional form.

The leading cases show how courts have responded to constitutional reform without openly abandoning parliamentary sovereignty.

Thoburn is the starting point for modern constitutional statutes. Laws LJ rejected the idea that all statutes are equal for all purposes. Constitutional statutes condition the legal relationship between citizen and state, or enlarge or diminish fundamental rights. They are not subject to implied repeal. The case matters because it gives the common law a role in classifying legislation. That does not mean courts can refuse express repeal. It does mean constitutional change must be clear. Thoburn therefore links Weeks 2 and 3 to Week 12: sovereignty survives, but the common law structures its operation.

Jackson concerned the validity of the Hunting Act 2004, enacted using the Parliament Acts procedure. The House of Lords upheld the Act, but the constitutional importance lies in the dicta. Several Law Lords questioned whether parliamentary sovereignty was absolute in all conceivable circumstances. The case remains controversial because the remarks were not necessary to the result, yet they are impossible to ignore. Jackson is best used as evidence of judicial constitutional anxiety, not as authority that courts may now strike down Acts of Parliament.

Miller (No 1) concerned whether ministers could use prerogative power to notify withdrawal from the EU under Article 50. The Supreme Court held that legislation was required because notification would lead to changes in domestic law and rights created under the European Communities Act 1972. The case is about reform by executive act. Major constitutional change could not be achieved by prerogative where Parliament had created the relevant legal order.

Miller (No 2), with Cherry, concerned prorogation during the Brexit crisis. The Supreme Court held the prorogation unlawful because it had the effect of frustrating or preventing Parliament from carrying out its constitutional functions without reasonable justification. The decision is an important example of judicial enforcement of constitutional principles in a politically charged context. It did not deny parliamentary sovereignty; it protected Parliament’s ability to exercise it.

Evans demonstrates judicial resistance to executive override of legality. The Attorney General used a statutory power to issue a certificate overriding a judicial decision requiring disclosure of Prince Charles’s advocacy correspondence. The Supreme Court quashed the certificate. The constitutional point is that a minister cannot lightly be authorised to nullify the practical effect of a court decision. Statutory language is read against rule-of-law assumptions.

Privacy International is the leading modern case on ouster clauses. The Supreme Court held that the relevant provision did not exclude judicial review for error of law by the Investigatory Powers Tribunal. Its significance for constitutional reform is plain: attempts to redesign institutional accountability by excluding courts will be interpreted strictly. The case has direct relevance to later legislative attempts to use more express ouster language.

AXA concerns devolution and the status of Acts of the Scottish Parliament. The Supreme Court held that such Acts are primary legislation for important purposes but remain reviewable for competence. The case shows the hybrid nature of devolution: devolved legislatures are democratically legitimate law-makers, but legally bounded by statute.

The Scottish Independence Reference confirms that devolution remains legally structured by the Scotland Act. The Supreme Court held that a Bill for an advisory referendum on Scottish independence would relate to reserved matters and was outside devolved competence. The case illustrates the gap between political claims of constituent authority and legal rules of competence. That gap is one of the central features of the changing constitution.

See practice questions section below.

See further reading section below.