Abstract
<jats:title>Abstract</jats:title> <jats:p>This chapter examines the 2016 Brexit referendum as the critical moment that transformed an issue of low public salience into the basis for enduring political identities. We outline how the referendum met three key conditions for the emergence of issue-based identities: high levels of issue contestation, widespread opportunities for issue expression, and a lack of alignment with traditional party divisions. Drawing on evidence from the campaign and its aftermath in Parliament and beyond, we show how the binary nature of the referendum increased the salience of EU membership, forced individuals to express a clear stance, and presented ambiguous partisan cues due to divided party leadership. This context facilitated the creation of two new identity groups: Leavers and Remainers. The chapter argues that other specific features of the Brexit referendum, including the continued partisan divisions and public debate following the vote, sustained the salience of the issue and reinforced the emerging tribal divide. We thus highlight how certain political events, such as referendums, at certain times, such as 2016, can act as catalysts for identity formation.</jats:p>