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Judicial review, human rights, parliamentary sovereignty — 29 constitutional cases
Public Law is the branch of UK law that governs the relationship between the state and the individual, and among the institutions of government themselves. Its central question is simple but fundamental: where does legal authority come from, and what happens when those who hold power overstep it? It spans constitutional law — the rules about how government is structured and legitimised — and administrative law, which polices how public bodies exercise the powers Parliament has given them.
Four doctrines give the subject its backbone. Parliamentary sovereignty holds that Parliament is the supreme law-making authority, capable of enacting or repealing any law — yet cases like Thoburn and Jackson have opened serious debate about whether that supremacy is truly unlimited. The rule of law insists that everyone, including the government, is bound by law and that executive action must have clear legal authority. Judicial review gives the courts their toolkit for scrutinising public decision-making, using the grounds of illegality, irrationality (the Wednesbury standard), and procedural impropriety established in the CCSU case. The Human Rights Act 1998 then overlays these common-law controls with Convention rights, requiring courts to read legislation compatibly where possible and to declare incompatibilities where it is not.
Several tensions sit at the frontier of the subject and separate a competent student from a strong one. The relationship between parliamentary sovereignty and constitutional rights is genuinely unsettled: Evans and Privacy International both pressed the question of how far courts can check even primary legislation or statutory tribunals. The scope and intensity of proportionality review — whether it should replace or supplement Wednesbury — remains contested after Bank Mellat and Daly. Finally, the constitutional limits of prerogative power, dramatically illustrated by Miller and the Fire Brigades Union case, continue to generate live controversy about who really controls the executive in a modern democracy.
Parliament is the supreme legal authority in the UK and can make or unmake any law; no court may strike down an Act of Parliament, though the boundaries of this principle are increasingly contested. Some judges have suggested there may be constitutional limits that even Parliament cannot override.
A public body acts unlawfully if it acts outside its legal powers (illegality), reaches a decision so unreasonable that no rational authority could have made it (irrationality), or fails to follow fair procedures (procedural impropriety). These three heads of review, confirmed in CCSU, remain the organising framework for challenging public decisions.
The executive has no power to act against individuals without clear legal authority, whether statutory or under the prerogative; any purported power must be traceable to a lawful source. Courts will hold the government to account even where it acts in the name of the Crown.
Where Convention rights are engaged under the Human Rights Act 1998, courts apply a structured proportionality test that is more searching than bare Wednesbury unreasonableness, asking whether an interference with a right is rationally connected to a legitimate aim and goes no further than necessary. The courts must also read legislation compatibly with Convention rights so far as it is possible to do so.
A public body must act fairly before making a decision that adversely affects an individual, which ordinarily requires notice and an opportunity to be heard; where a body has made a clear and unambiguous promise or established a consistent practice, it may be held to that expectation unless there is a good public-interest reason to depart from it. These duties arise from the common law, independently of statute.
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