Geoffrey Cox succeeded in comprehensively spiking the Strasbourg concessions he secured on the backstop with his own legal advice stating that the “legal risk remains unchanged”. Now with the benefit of a few more days to analyse them, a group of top pro-Brexit lawyers have written a report for Policy Exchange arguing that Cox got his own advice wrong. They say: “The risk of the backstop being used as leveraging for the next phase of the negotiations to lock the EU into a backstop-like arrangement indefinitely has receded significantly”.

The paper is co-authored by Professors Guglielmo Verdirame QC and Richard Ekins, and former First Parliamentary Counsel Sir Stephen Laws. They say that the Strasbourg concessions mean that the EU would be breaching “good faith” to dismiss all alternative solutions to the Irish border, particularly in light of the fact that the “EU is fully apprised of the fact that the UK’s present objective is to leave the Single Market and the Customs Union”, concluding that:

“It would be clearly incompatible with its obligations under the Withdrawal Agreement, Protocol, and Joint Instrument, for the EU to adopt a negotiating stance that boils down to the position that only ‘backstop 2.0’ can replace the current backstop.”

Cox has now updated his legal advice to say that the UK would have the right to invoke Article 62 of the Vienna Convention to withdraw from the treaty in “exceptional circumstances”, for instance if the “the prolonged operation of the Backstop was having a socially destabilising effect in Northern Ireland.”

The Brexit ‘Star Chamber’ has rejected Cox’s latest advice, but Cox has found support from an unlikely source in Remoaner lawyer Lord Pannick QC, who led and won Gina Miller’s Article 50 legal challenge. While Pannick reiterates his support for a second referendum, he concludes that, as a matter of law:

“If the UK were therefore to be faced (against its will) with a permanent backstop arrangement, the UK would be entitled to terminate the withdrawal agreement under Article 62 of the Vienna convention on the Law of Treaties.”

Ultimately, the Government has backed Brexiteer MPs into such a tight corner that they are now facing a political choice as much as a legal one. Even if the Vienna Convention route does not hold, the UK still retains the nuclear option of unilaterally tearing up the the treaty altogether if it feels the consequences of that are preferable to a permanent backstop. If the UK fails to leave at all, the political establishment will never allow the country to even get a sniff of the exit door ever again…