The Government White Paper has made one thing clear: leaving the EU will end the jurisdiction of the Court of Justice of the European Union (CJEU) . The Government’s red line may appear absolute, but as with many of the intricacies of Brexit, how this will operate in practice, and the wider ramifications for criminal justice and policing, continue to cause confusion and uncertainty. Two key questions remain without a definitive answer: what will be the effect of the CJEU decisions once we remove ourselves from its jurisdiction, and what, if any, system will take its place?
The current UK position
Unlike other Member States, the UK has taken a selective approach to EU measures on policing and criminal justice. Prior to 2013, the UK signed up to Pillar 3 of the Maastricht Treaty, which concerned Justice and Home Affairs. However, in 2013 the UK exercised its option under the Treaty of Lisbon, to block opt-out of approximately 130 police and criminal justice measures adopted before the Treaty entered into force. The UK chose to opt back in to 35 measures, including EUROJUST, EUROPOOL, measures aimed at tackling cybercrime, human trafficking, child pornography, as well as mutual recognition of confiscation and financial penalties, amongst others. Most notably, the UK opted into the European Arrest Warrant (EAW) and by doing so, the UK accepted that the regime would be subject to the jurisdiction of the CJEU.
How will CJEU decisions be treated post-Brexit?
Policing and Crime measures have been shaped throughout the years by CJEU jurisprudence, and CJEU decisions have real and significant effects on the liberty of individuals to whom they relate. The Department for Exiting the European Union in its position paper entitled Ongoing Union Judicial and Administrative Proceedings, has stated that historic case law will be given the same binding status in UK courts as the UK Supreme Court, who can depart from previous judgments where appropriate.
A particularly ambiguous point remains however, which is how UK judges should approach CJEU decisions decided post-Brexit, with senior members of the Judiciary seeking clarity from the Government on this point. Lord Neuberger has voiced concerns that without a clear position, judges will ‘simply have to do their best’, but risk being unfairly blamed for making the law where Parliament has failed.
If judges are instructed to ignore post-Brexit judgments entirely, the UK risks being out of step with Member States with whom it wishes to maintain cooperative criminal justice measures. More likely, on the basis of the Government’s current stance, judges will be instructed to take account of CJEU decisions as persuasive rather than binding. The weight to be afforded to these however, and the extent to which the UK should look to Europe, is an area of uncertainty with the potential for creating inconsistency and conflict.
A replacement for the CJEU?
The wider question remains: without the CJEU, how will the UK continue to operate and cooperate with Member States on issues such as criminal justice? Reclaiming legal sovereignty has been central to the Brexit debate, but if the UK is to continue to contribute at an international level in tackling crime, there must be an overseeing entity able to level the playing field. Decisions of the CJEU have direct effect on individuals, and arguably the most transparent and enforceable process for ensuring fairness and uniformity in such cases, is a court. Whether Member States would be willing to negotiate and create a bespoke adjudication platform to settle disputes with the UK remains to be seen. The Government policy paper on dispute resolution considers potential alternative models for settling disputes between the UK and the EU, once “direct” jurisdiction ends. Many suggest, however, that whatever form the parallel system takes, it will be the CJEU in all but name.
The role of the CJEU in the UK’s future rumbles on in Parliamentary debate. A number of questions are in dire need of answering if the UK is to continue to participate either directly in pre-established EU policing and criminal justice measures, or through new agreements with Member States. The CJEU’s reach is wide, and whilst under its jurisdiction, decisions have bound and influenced at a Governmental and individual level. Ultimately, untangling ourselves from its reach has the potential for significant knock on effects on the UK’s ability to contribute to, and benefit from the international approach to the ever increasing cross-border nature of crime.
 Department for Exiting the European Union, The United Kingdom’s exit from and new partnership
with the European Union, para 2.3: https://www.gov.uk/government/publications/
 Department for Exiting the European Union, Ongoing Union Judicial and Administrative Proceedings, para 14: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/627910/FINAL_OFF_SEN_Position_paper_HMG_Ongoing_Union_judicial_and_administrative_proceedings_Position_Papers_FINAL_120717__2___1_.pdf
 Department for Exiting the European Union, Enforcement and dispute resolution – a future partnership paper: https://www.gov.uk/government/publications/enforcement-and-dispute-resolution-a-future-partnership-paper
 Sir Paul Jenkins, Matrix Chambers https://www.theguardian.com/politics/2017/aug/19/brexit-european-court-of-justice-theresa-may-foolish-attack