The United Kingdom: First-Past-the-Post and Westminster Democracy

The Westminster System: Parliamentary Sovereignty Without a Written Constitution#

The United Kingdom's political system is the archetypal Westminster model — the template from which parliamentary systems across the Commonwealth, and many beyond it, were drawn. Yet it has a feature that distinguishes it radically from virtually every other stable democracy: the United Kingdom has no single written, codified constitution. Its constitutional arrangements exist in a web of statutes, common law precedents, parliamentary conventions, and historical documents stretching back to Magna Carta (1215).

Parliamentary Sovereignty: The Master Principle#

The foundational doctrine of the British system is parliamentary sovereignty (or parliamentary supremacy): Parliament — specifically the House of Commons, House of Lords, and the Crown acting together — can make or unmake any law, and no court can strike down an Act of Parliament as unconstitutional (though courts can interpret legislation and, since the Human Rights Act 1998, issue "declarations of incompatibility" with European human rights standards).

This contrasts directly with both the United States and Germany, where courts hold the power of judicial review and can void legislation that contradicts the supreme constitution. In the UK, no such hierarchy exists: a simple parliamentary majority can, in principle, do anything. This makes Parliament the supreme political authority — but it also means that constitutional protections depend primarily on political convention and culture rather than enforceable legal rules.

The Prime Minister and Cabinet Government#

Unlike the U.S. president (separately elected, fixed term) or the German Bundespräsident (largely ceremonial), the British Prime Minister holds no separate electoral mandate. The PM is, formally, simply the Member of Parliament best able to command a Commons majority — almost always the leader of the largest party after a general election.

This creates a system of fusion of powers: the executive (Cabinet) is drawn from and sits within the legislature. Ministers are MPs (or Lords); the Prime Minister is an MP who must appear regularly in the Commons for Prime Minister's Questions (PMQs), a weekly accountability session with no equivalent in presidential systems. The government exists only as long as it maintains the confidence of the Commons — a vote of no confidence can bring it down.

Comparison with Germany#

Both Germany and the UK operate parliamentary systems, but with key differences:

Germany's Grundgesetz was explicitly designed by post-war democrats who had watched the Weimar Republic collapse. Its "eternity clauses" entrench core democratic principles beyond the reach of any parliamentary majority. The UK's uncodified system, by contrast, relies on centuries of convention — a system that works well in stable conditions but provides fewer formal safeguards against authoritarian drift.

Sources: A.V. Dicey, An Introduction to the Study of the Law of the Constitution (1885, 10th ed. 1959) (Tier 1 classic); Human Rights Act 1998, c. 42 (Tier 1); Arend Lijphart, Patterns of Democracy (Yale University Press, 2nd ed., 2012) (Tier 2).