15 UK Landmark Constitutional Cases Guide 2026

The case established that the Crown could not use a proclamation to change the common law, statute law or create a new offence. It is a foundational authority for the proposition that prerogative power exists only so far as the law permits.

Government officials searched Entick’s home and seized papers under a general warrant. The court held the entry and seizure unlawful because the government could not identify lawful authority for the interference. The case is a foundation of the rule of law and protection of property and liberty.

The Crown had taken possession of a hotel during the First World War. The House of Lords held that where Parliament had legislated for the relevant power and compensation, the Crown could not rely on prerogative power to avoid the statutory compensation regime.

The House of Lords treated a material error of law as capable of rendering a tribunal decision legally invalid and rejected the argument that the statutory ouster clause prevented the courts from examining whether a legally valid determination had been made.

The House of Lords confirmed that an exercise of prerogative power can, in principle, be subject to judicial review. The familiar grounds of illegality, irrationality and procedural impropriety were articulated, while national-security considerations affected the justiciability of the particular decision.

The House of Lords relaxed the traditional exclusion of parliamentary debates as an interpretive aid. In specified circumstances, including ambiguity or obscurity, courts may refer to clear ministerial statements in Hansard when interpreting legislation.

The case concerned prisoners’ access to journalists. The House of Lords held that fundamental rights are not overridden by general or ambiguous statutory language unless Parliament clearly confronts the interference. The decision is a central statement of the common-law principle of legality.

The court distinguished constitutional statutes from ordinary statutes and stated that constitutional statutes are not normally subject to implied repeal. The case was decided while EU law had domestic effect through the European Communities Act 1972; its EU-law supremacy reasoning must now be read in the post-Brexit constitutional context.

The House of Lords rejected the challenge to the validity of the Parliament Act 1949 and therefore upheld the Hunting Act 2004. Several speeches nevertheless discussed, in obiter observations, whether there could be legal limits to parliamentary sovereignty.

The Supreme Court considered a challenge to Scottish legislation and discussed the constitutional nature of the rule of law, the limits of legislative competence and the relationship between courts and legislatures within the Scottish constitutional framework.

The Supreme Court considered the Attorney General’s attempt to veto disclosure of correspondence under freedom-of-information legislation. The majority treated the statutory veto and the constitutional role of the courts with particular caution and rejected the use of the veto in the circumstances.

The Supreme Court held that the government could not notify the EU under Article 50 using prerogative power alone because doing so would inevitably lead to changes in domestic law and remove statutory rights. An Act of Parliament was therefore required.

The Supreme Court unanimously quashed employment tribunal fees. The court held that access to courts and tribunals is a constitutional right and that the fees imposed an unlawful impediment to the enforcement of employment rights.

The Supreme Court considered whether an ouster clause could prevent judicial review of Investigatory Powers Tribunal decisions. The judgment strongly affirmed the constitutional importance of judicial supervision of legality and treated a total exclusion of review with exceptional caution.

The Supreme Court held that the Prime Minister’s advice to prorogue Parliament was justiciable and unlawful because it had the effect of frustrating or preventing Parliament from carrying out its constitutional functions without reasonable justification. The prorogation was therefore void and of no legal effect.

Constitutional Themes Across the Cases

Brexit and the Post-2016 Constitutional Context

Some older constitutional cases involving EU law must be read historically. Thoburn, for example, concerned the domestic constitutional status of EU law under the European Communities Act 1972. Following the UK's withdrawal from the EU, EU-law supremacy no longer operates in the same constitutional form.

Miller [2017] is particularly important because it addressed the constitutional route for using prerogative power to begin the withdrawal process. Miller/Cherry [2019], by contrast, focused on prorogation and the constitutional role of Parliament.

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