The rule of law

Alongside parliamentary sovereignty, the rule of law is one of the two great pillars of the United Kingdom’s constitution. At its simplest, it holds that everyone — including the government and those who govern — is subject to the law and equal before it, and that power must be exercised according to known legal rules rather than arbitrary will. It is an idea with a long history and a continuing practical force, shaping how the courts, the executive and Parliament relate to one another and protecting the individual against the abuse of power.

The core principle

The rule of law stands in opposition to arbitrary power. Where the rule of law prevails, those in authority cannot simply do as they please; they must act within legal limits, and their actions can be tested in the courts. This has several strands. Equality before the law means the law applies to everyone alike, regardless of status, wealth or office — government ministers and officials are subject to the same law as ordinary citizens and can be held to account in the courts. No one is above the law, however senior. And power must be exercised according to general, known rules rather than the unpredictable preferences of rulers, which makes the actions of government both predictable and accountable.

The classic British exposition came from A.V. Dicey in 1885. He set out three ideas: that no one can be punished except for a definite breach of law established before the ordinary courts; that everyone, whatever their rank, is subject to the ordinary law and the jurisdiction of the ordinary courts; and that the general principles of the constitution result from the decisions of judges in particular cases. A more recent and influential account came from the senior judge Tom Bingham, whose 2010 book identified principles such as the accessibility and clarity of law, equality before the law, the exercise of power within legal limits, the protection of fundamental rights, fair adjudication, and compliance with international law obligations.

Due process and legal certainty

Two requirements give the rule of law practical content. The first is due process — the demand that legal proceedings be fair. People must receive notice of any action against them, a fair hearing before an impartial tribunal, and a genuine opportunity to put their case. Due process ensures that the law is applied through fair procedures, not arbitrarily, and that even those accused of serious wrongdoing are treated justly.

The second is legal certainty. Laws should be clear, public, prospective (forward-looking) and reasonably stable, so that people can know in advance what the law requires and order their affairs accordingly. Laws that are vague, secret or retrospective undermine certainty: if citizens cannot know the rules in advance, or if the rules change unpredictably or punish past conduct that was lawful when done, the protective function of law collapses. Predictable, knowable law is therefore central to the whole idea.

An independent judiciary

None of this can work without an independent judiciary. The law can only restrain government and protect individuals if judges decide cases impartially, free from political pressure. Judicial independence ensures that disputes — including those brought against the state itself — are decided on the law and the facts, not on the wishes of politicians.

In the UK, judicial independence is protected in several ways. Judges have security of tenure and cannot easily be removed; their pay is protected from interference; and the Constitutional Reform Act 2005 strengthened the separation between the judiciary and the government. That Act established the UK Supreme Court, replacing the judicial role of the House of Lords, and created an independent process for appointing judges, reinforcing the line between those who make law and those who interpret and apply it.

Holding power to account

The rule of law is made effective in practice above all through judicial review — the process by which courts examine whether public bodies have acted lawfully, within their powers and fairly. Through judicial review the courts can check unlawful government action, requiring ministers and public authorities to stay within the limits the law sets. This is the rule of law in operation: a mechanism by which the executive is held to the law and the individual is protected against the unlawful use of state power.

Equally important is access to justice. Legal rights are only meaningful if people can actually enforce them. The rule of law therefore requires that individuals can bring claims and have disputes resolved by the courts; barriers such as excessive cost can hollow out the principle by leaving rights unenforceable in practice, however clearly they exist on paper.

The rule of law and sovereignty

How does the rule of law sit alongside parliamentary sovereignty? The two can appear to be in tension. Sovereignty says Parliament can make any law it likes; the rule of law stresses limits on arbitrary power and the protection of the individual. In practice, the British constitution holds the two together. Parliament legislates and is legally supreme, but the courts interpret and apply the law, ensure fair procedures, and hold the executive to account through judicial review. Both principles are regarded as foundations of the constitution, and the ongoing negotiation between them — between the supremacy of the elected legislature and the independent authority of law — is one of the defining features of the British constitutional order.