Debates in and over the European Union (EU) are increasingly characterised as being based in arguments that are either ‘populist’ or ‘technocratic’. As systems of communication, this article argues, populism and technocracy possess dramatically different logics of argumentation, modes of communication and meaning-making, distinct narratives, with appeals to distinct sources of legitimacy. As such, actors adopting either political style construct their identity in a way that seeks to legitimise its own political action, while in turn delegitimising that of its opponents. This results in an atmosphere of distrust between actors using these different communication styles, making any form of negotiation or cooperation between them exceedingly difficult. In the context of the Brexit negotiations, which this article uses as a case study, the UK Government has adopted a populist style characterised by narratives of taking back control, legitimised by the will of the people, communicating often in a ‘low’ political style and using a narrative of crisis and threat. In comparison, the EU has adopted a technocratic style characterised by narratives of technical policy making and the need for rationality, legitimised through the laws, rules and processes by which it is governed, communicating in a ‘high’ political style while using a narrative of stability and continuity. These radically different views of the world have resulted in an increasing of tensions and distrust by the parties to Brexit negotiations that were already heightened by a sense of ‘betrayal’ over Brexit.