Catherine Barnard, professor of EU law Cambridge University, said that allowing the Article 50 divorce proceedings to become a permanent state of affairs, or a backdoor to remaining in the EU, would inevitably invite a court challenge.
Under EU law, the Article 50 ‘divorce deal’ can be agreed after a majority vote by EU member states, but comprehensive trade deals with independent countries – which the UK will become after Brexit – must be unanimously agreed under Article 218.
“Article 50 says nothing on transition. All it contains is a reference to ‘taking account of the framework for its future relationship with the Union’ but that allows us to read transitional arrangements into that language,” she explained.
“However if a transition period went on too long, it’s highly likely someone might challenge the legality by arguing this transition has become a de facto trade agreement and is circumventing the requirement that trade deals are negotiated under Article 207 or Article 217 and the legal procedures set out under Article 218.”
Because of the lack of specificity in Article 50 there remains legal grey areas over how long a transition could be permitted under Article 50.