The Guardian view on the Welsh and Scottish elections: Plaid’s triumph heralds a new era in devolved politics | Editorial

Progressive nationalist parties now hold power in Edinburgh, Cardiff and Belfast. That will be a challenge for the United Kingdom’s overcentralised state

When the Scottish and Welsh assemblies were created on the eve of the millennium, the then Labour government in Westminster believed that it had engineered a win-win situation. Devolution, it was hoped, would see off any nationalist threat in Scotland and Wales. Meanwhile, the Labour party’s longstanding political dominance in both nations would see it take comfortable control of the two new parliaments.

That was then. Last week’s devolved elections left Scottish and Welsh Labour battered, bruised and humiliated. Plaid Cymru’s historic victory in Wales, and a fifth successive triumph for the Scottish National party (SNP), mean that pro-independence governments are now set for the first time to rule in Edinburgh, Cardiff and Belfast (where Sinn Féin won in 2022). The starting gun has been fired on a new and constitutionally contested era in the politics of the UK.