This paper considers the implications of Brexit as an interplay of law, regulation and justice, using a tripartite conceptualisation. First, as an EU Member State, the UK has been involved in EU law-making as EU ‘rule-maker’. However, within this first conceptualisation, in many instances, existing EU rules entrenched into domestic law will continue to apply, as an unique example of ‘rule-maker’ turned ‘rule-taker.’ Second, as a Third Country , the UK will inevitably become subject to what is referred to as the ‘Global Reach of EU Law’, becoming a ‘rule-taker’. Third, debates on Brexit indicate that the UK’s withdrawal from the EU present challenges to the post-Brexit EU-UK regulatory relationship and its subjects and objects. Where voids in regulation emerge, the likelihood of injustices emerge. This paper explores the methodological tools needed to assess rigorously this interplay between rule-maker, rule-taker and rule-void going forward, with respect to law, regulation and justice.