Electoral Realignment: How Brexit Reshaped British Voting Behaviour provides a novel account of electoral change, focusing on how electoral shocks in general—and Brexit in particular—have reshaped the relationship between social and demographic characteristics and voting behaviour in Britain. Drawing on a wide array of data, Edward Fieldhouse, Jane Green, Christopher Prosser, Geoffrey Evans, Jack Bailey, and Jonathan Mellon examine how the vote to leave the European Union in 2016 led to fundamental change in 'party supply'—most notably a shift in the position of the Conservative Party on Europe—in turn accelerating the ongoing realignment of British politics around social and cultural issues. Through 'sorting' voters by their Brexit preferences, age and education have become the most important demographic predictors of vote choice, with realignment reaching its height during the 2019 General Election. Electoral Realignment examines the argument that the key to understanding realignments, is through political reactions to electoral shocks and through the combination of changing voter demands and the strategic responses of political parties. This book covers topics such as changing values, Brexit and competence shocks, and draws attention to the idea that the electoral shocks that rocked British politics after 2020 were primarily about competence rather than being ideological in nature. Drawing on data from British Election Studies covering over sixty years, Fieldhouse et al explore how the decade from 2015 to 2025 witnessed a shift in the relationship between party preferences and social class, education, geography, age, and political values, providing readers with an in-depth understanding of electoral realignment in Britain in a long-term context. This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations.