Already the Electoral Reform Society is arguing that this byelection illustrates everything wrong with first past the post (FPTP): campaigns bogged down in arguing over who can beat whom rather than what anyone actually stands for inside a system designed for a world that no longer exists. FPTP’s winner-takes-all design is built around the idea of two main parties and prioritises the swift formation of majority governments: though harsh on smaller parties, it’s done a sterling job of keeping extremists out of British politics for decades, even as the far right surged across Europe. What it doesn’t cope well with is both main parties falling apart in quick succession, creating a three- or four-party system in which candidates can win big on worryingly low shares of the vote. What put the cat among the pigeons was a YouGov model last autumn showing Reform could in theory win 48% of the seats at Westminster – just shy of a majority – on as little as 27% of the vote, most likely leaving almost three-quarters of the country with the leader it didn’t want.