The Brexit process has been characterised by hyper-litigation – an unprecedented level of strategic litigation brought to influence the process, substance and/or the politics of the UK’s departure from the European Union. Although strategic litigation is by no means unknown in the UK context, we argue that the volume, and unusual degree of success, of Brexit-related litigation may represent a further step change in the use of strategic litigation in the UK constitutional context.

In this chapter, we catalogue more than 50 instances of Brexit-related strategic litigation in the UK, EU and other European courts, up until the date of the UK’s departure from the EU on 31 January 2020. We analyse, first, by whom, about what, and with what aims cases were brought. Secondly, we discuss the impacts of the litigation, both in legal terms – seeking to identify why some cases succeeded where others did not – and in terms of their broader political effects. Thirdly, we try to account for hyper-litigation, identifying the various factors encouraging resort to the courts. Finally, we consider the likely long-term impacts of Brexit-related strategic litigation, and the potential for backlash against politically-motivated litigation by both political actors and the courts themselves.