What is happening to political parties? In the classic historical profile, parties were terminated, despite their struggles to survive, by the advent of a more attractive rival or by voters’ gradual disengagement. Over the past three years, however, we have witnessed the spectacle of the Conservative Party committing suicide, starting from the base of an 80-seat majority and the unlooked-for conversion of Labour’s Red Wall electorate – a phenomenon that offered the prospect of a permanent electoral revolution keeping the Tories in power indefinitely.