Christina Lienen: Brexit and the Domestic Judiciary: Some Preliminary Thoughts on the Aftermath of Triggering Article 50

0d84564This week saw the first legal action concerning the constitutional requirements surrounding the Brexit process being initiated. With or without Parliamentary consent, we now know that the two year negotiation period under Article 50 will only be triggered in 2017. Once negotiations have officially started, it is expected that there will be some sort of political agreement on the post-Brexit EU-UK relationship. It will not be until at least early 2019, however, that a clear path towards the disentanglement of these two sophisticated legal orders will fully begin to crystallise. In the worst case scenario, by the end of the two year period we may find ourselves forced to leave without a comprehensive agreement, should it be rejected by the European Parliament (Article 50(2)) or if no qualified majority can be reached in the Council. Here the qualified majority is defined as at least 72% of the members of the Council, with the additional requirement that the votes represent at least 65% of the population of the EU (Article 238(3)b). The UK will not be part of this vote. If there is no agreement with the UK then UK membership would end automatically, unless the European Council and the UK decide jointly to extend this period.

At this stage, it is difficult to predict exactly how the UK courts will adjudicate cases involving EU law in the immediate future. There are three main timeframes: (1) Post-Brexit referendum but Pre-Article 50 notification, (2) post Article 50 notification but prior to conclusion of the withdrawal agreement, (3) post withdrawal disentanglement and replacement of national law from EU law post withdrawal agreement. Under Article 50(3) the Treaties will only ‘cease to apply from the date of entry of the withdrawal agreement or, failing that, two years after the notification’. From that moment in time EU Law (the TEU and TFEU and post Brexit CJEU case law and secondary legislation and decisions) would cease to apply in the withdrawing state. Under the most straightforward view, the UK will be bound by EU law under its international law obligations until the end of the two year period after Article 50 has been triggered. However, I suggest that it is more complicated than that. Firstly, UK courts value consistency and fairness. It is therefore hard to imagine that a case coming to the UKSC a few months before the two year period runs out would be decided giving full effect to EU law where such a decision in a similar case immediately after Brexit could easily be challenged. Secondly, and perhaps more importantly, in some areas it is incredibly difficult to determine what aspects of a legal rule or legal thinking are influenced or created by EU law, and which ones are purely domestic. Grasping and disentangling 40 years of European Union law and domestic law will be, as Mark Elliott puts it, a herculean effort. It is impossible to address these two concerns conclusively in a blog post. Instead, I would like to flag a few issues concerning one particular type of EU legislation that is likely to cause some constitutional struggle – EU Directives.

O’Brien v Ministry of Justice, a case currently before the UK Supreme Court (UKSC), is about the appellant’s entitlement to a pension under the Part Time Workers Directive (97/81/EC) which the United Kingdom had to (and did) transpose into domestic law by 7 April 2000. Counsel for Mr O’Brien argue that the appellant is entitled to have his service prior to the transposition date taken into account for the purpose of his pension calculation. The hearing finish date was the 7th of July 2016; shortly after the result of the referendum was known. At this stage, it is highly unlikely that the UKSC would arrive at a conclusion which gives anything other than full effect to EU Law. There are no direct legal implications of the referendum at this stage. But jump a few years ahead to a fictitious case with similar characteristics and we begin to appreciate some of the challenges the courts will be facing. What if, in the fictitious future case, the UK had not transposed the Directive in question? Under the doctrine of direct effect, famously established by the seminal CJEU judgments of Van Gend en Loos, Costa/ENEL (both featuring on the 50 Problematic Cases list of the Judicial Power Project) and Van Duyn, individuals can rely directly on EU Directives. This is subject to the conditions that (i) the Directive is clear, precise and unconditional, (ii) it is not dependent on further legislation/action by the Member State or the EU, and (iii) the date of implementation has passed. Whilst the UK has a comparatively low compliance deficit of 1%, the average delay of transposing is 11.9 months, which means that Directives are likely to be relied on which the UK will not implement on time (as ministers are figuring out what to do about Directives during the negotiation period in the first place) as well as Directives that will not have been implemented at all (should Parliament choose not to implement Directives passed whilst it was still officially an EU member, or such Directives passed in the negotiation period). This uncertainty may have consequences for public entities subjected to obligations under EU law. Moreover, under the doctrine of indirect effect national courts are required to interpret domestic legislation in light of EU Directives in horizontal situations. Thus individuals and private companies will also be facing a period of legal limbo regarding their obligations under EU law.

Furthermore, it is uncertain whether the continuing applicability of EU law and its disentanglement from domestic law is a matter of national constitutional law or a matter of EU law. If the latter is the case, we could be facing the very intriguing possibility of a preliminary question to the CJEU, given that the doctrines of acte éclairé and acte clair are clearly not applicable. Should EU law govern the transition period leading up to the exit agreement, EU general principles, which are considered equal in their legal value to Treaty articles, would apply. The main candidate to be considered here is the rule of law, which is informed by the substantive rules of legal certainty, the principle of confidence in the stability of a legal situation and the principle of proportionality. The domestic principles guiding us through these issues on the other hand are the UK’s understanding of the rule of law, constitutionalism and parliamentary sovereignty.

In conclusion, due to the disentanglement of EU law and domestic law and considerations of consistency and fairness, it is difficult to predict exactly how the UK courts will adjudicate cases involving EU law in the immediate future. There are three main possibilities for the post-Article 50 legal landscape. The courts will fully adhere to EU Law and apply it as if the referendum and/or Brexit had not happened for a while; they will adhere to EU Law but give partial or complete preference to domestic law where there is a discrepancy; or they will find a way of starting to disregard EU Law altogether. Directives may prove to be particularly challenging in this context due to their legal nature. Besides O’Brien, other cases involving complex questions on EU law, such as a blanket denial of social welfare assistance to Zambrano carers, are currently before the UKSC. The number of court cases involving EU law is likely to increase at all judicial levels in the near future given people’s anxieties about their legal status and rights. Constitutional lawyers have on numerous occasions been intrigued by the legal reasoning of the UKSC in cases involving EU law. I suspect that we will be in for a treat once the Article 50 trigger is pulled. The courts will be the first ones to actually having to deal with the uncertainty caused by the Brexit process – let’s hope that it will unfold in a less dramatic way than what we have seen over the past few of weeks.

Christina Lienen is a PhD Candidate (LAHP) at University College London. She would like to thank Richard Rawlings, Piet Eeckhout and Jeff King for their much appreciated comments on an earlier draft of this piece.

(Suggested citation: C. Lienen, ‘Brexit and the Domestic Judiciary: Some Preliminary Thoughts on the Aftermath of Triggering Article 50’ U.K. Const. L. Blog (21st July 2016) (available at: (available at: