Is American-style partisan polarization invading UK politics?

The generation most steeped in algorithmic politics turned out to be the least convinced by the thesis. Voters in their mid-thirties to mid-forties split down the middle on whether US-style partisan tribalism has colonised Westminster, even as the rest of the chamber, from the youngest to the oldest, answered yes with real conviction, the over-65s unanimously so.

That fracture sits oddly against the received story, that it's the young who've absorbed American culture-war categories through social media. Here it was the 55-64s and 25-34s, not the middle-aged, who voted most heavily that polarisation has crossed the Atlantic, while men were notably more convinced than women, who arrived at yes by a narrower margin.

The result lands squarely on a live fault line: Brexit's realignment of politics around identity rather than class, the reflex import of American language on race and gender, and worries that first-past-the-post and a fracturing multi-party system leave Britain more vulnerable to tribal sorting than its institutions were built for.

That the doubters cluster in a single age band, rather than across a clean generational line, suggests this isn't simply a story about who grew up online.