Never has a Welsh Senedd election seemed so interesting; the Caerphilly by election marks a true turning point in history. It is the moment when the duopoly that has ruled British politics for the past century finally crumbled. The question was never: could Labour hang on in the face of a challenge from an up-start party? Many by-elections have asked this. Rather, the question was this: which up-start party could benefit from Labour’s demise? Voters have shown that they are just as determined to do to the Labour party what they did to the Conservatives at the 2024 general election.

This the Balkanisation of UK politics, and it is going to make the next general election the most unpredictable in history. We haven’t seen the end of two-way contests – our first-past-the-post system will make

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