The British constitution is typically seen as not only a unique, but a uniquely conservative, set of political arrangements among the constitutions of the world. This characterisation stems from the constitution’s pre-modern origins and continuity over time, and its unwritten, traditional, and organic nature. This historical experience has been far from free of crises, fundamental changes (and reversals), or violent conflict. But the distinguishing feature of British constitutional history is the absence of a modern moment of revolutionary rupture, marking the shift of the state’s foundations from traditional rule to constitutional modernity and documentary constitutionalism.