I've heard it said in this last week that the Tories tend to fall apart after a decade in power. Examples: the end of SuperMac in the early 1960s ("thirteen years of Tory misrule"; Alec Douglas-Home provided the codicil); the end of Maggie Hatchett's reign (codicil: John Major); and now de Pfeffel's clown show (codicil: Sunak). That's not to say Labour don't also suffer from this (eg the Blaire/Brown years).

This methinks is ultimately a result of First Past the Post: each major party is itself effectively a coalition. Once any coalition has been in power for long enough, the tail ends up wagging the dog, and the coalition falls apart. In the UK, unlike under Proportional Representation, they can't then regroup with a different set of partners.

So: each major party can do one of two things: run the country, or combat its internal fragmentation. And *that*, mesdames et messieurs, is why each party needs a long time out of power for its headbangers to cool their heels.