INTRODUCTION

The exit of the United Kingdom from the European Union poses a series of questions regarding the future relationship of the UK with the EU and its Member States in the field of cross-border criminal cooperation, and the place of the UK in Europe's internal security architecture more broadly. This chapter will attempt to cast light on the legal position of the UK in this context aft er Brexit. In order to do so, it is necessary to place any future arrangements within the constitutional and structural context underpinning the evolution of Europe's area of criminal justice and the place of the United Kingdom within this area. The impact of Brexit to the UK's position in cross-border criminal justice cooperation will then be assessed, focusing on the impact of potential withdrawal from key EU cooperative mechanisms including on surrender (the European Arrest Warrant Framework Decision), on mutual legal assistance (the European Investigation Order Directive) and on policing (inter alia the Prüm instruments). The chapter will then go on to assess potential legal avenues of future UK association with the EU acquis and mechanisms of EU criminal justice cooperation. The chapter will demonstrate that any form of meaningful association or cooperation post-Brexit must entail compliance by the UK with the EU acquis, including with rulings of the Court of Justice of the European Union. Ironically, post-Brexit cooperation in the field of criminal justice may entail a higher level of compliance by the UK with EU law in comparison to its current position as an EU Member State: post-Brexit, the UK will have to comply with the EU acquis viewed in a holistic manner, rather than under the current UK's piecemeal, ‘pick-and-choose’ approach to EU criminal justice which has emerged as a consequence of the legal possibilities for UK ‘opt-outs’ from EU criminal law.