The 2016 referendum on membership of the European Union revealed a Britain fractured along generational, educational, class and regional lines. These cleavages presented substantial electoral problems to the main political parties, but for Labour they also posed an existential challenge.

This chapter explains how the Labour Party led by Jeremy Corbyn responded to these electoral and political challenges and will argue that the party's slow and erratic process of developing a policy that responded to the results of the 2016 referendum and to the tortuous process of withdrawing from the EU contributed to the party's disastrous results at the 2019 general election. In addition, the chapter will argue that the difficult process of agreeing to a “Brexit policy” exposed Labour's divisions and its existential and ideological crisis that had been brewing for the previous two decades.

Three key dilemmas explain Labour's slow, erratic and ultimately unclear response to Britain's decision to leave the EU: (1) the leader's ideological stances and statecraft; (2) electoral considerations; and (3) party cohesion. Seen in this light, Labour's slow response to these dramatic events reflects the challenges faced by power-seeking political parties that need to trade off permanently the not always compatible goals of promoting an ideology, winning elections, maintaining organizational cohesion and ensuring the survival of the party (Panebianco 1988; Harmel & Janda 1994: 248; Berman 2006: 11).

This trilemma was manifested in Labour's response to Brexit. If Corbyn's leftwing Euroscepticism informed most of his slow and indecisive responses to the various challenges the party faced, Brexit also presented Labour with electoral and ideological dilemmas. With an overwhelmingly pro-Remain membership, Labour was becoming a party of the young, educated, urban and cosmopolitan middle classes and was, as a result, more distant from its working-class historical electoral base, which was concerned with immigration and tended to gravitate towards socially conservative values. This diverse but divided electoral base was bluntly expressed in Labour's political geography: 70 per cent of Labour-held seats represented Leave areas (Hanretty 2016).