In some of London, in the Home Counties, in the south-west and a few parts of the Midlands and the north and quite a lot of Scotland, Conservatives will quietly applaud the man they believe guarantees their party victory at the next general election, meaning the Tories govern until at least 2025.

Fifteen years in power would represent the sort of era-defining political dominance that Margaret Thatcher and Tony Blair, in their very different ways, achieved, demolishing and demoralising their opponents in a way that inevitably gave rise to hubristic thoughts of permanent victory.

Yet in politics as in life, nothing is permanent. Changes can be hard to see coming, and the biggest changes can be the hardest of all to spot, even as they are under way.