Devolution transferred powers over health, education, transport, and other areas to Scotland, Wales, and Northern Ireland from 1999 onwards, creating new parliaments with real legislative authority. The Scottish Parliament has the most extensive powers, including limited tax-raising ability, while Wales and Northern Ireland have more constrained settlements. Westminster retains control over reserved matters including defence, foreign policy, immigration, and most taxation, and could theoretically abolish the devolved legislatures, though this would be politically explosive. The Sewel Convention says Westminster will not normally legislate on devolved matters without consent, but this is not legally binding, as Brexit demonstrated. Devolution has reshaped British politics, creating new centres of power and new tensions, and the future of the union remains uncertain.