My right hon. and learned Friend told my right hon. Friend Stephen Crabb that the European Union is refusing to allow a get-out clause on the permanent backstop, but he has also told us that he does not believe that the permanent backstop is sound in European Union law. Can this matter be resolved by a reference to the European Court of Justice in the same way that the European Court of Justice gave its opinion in relation to the relevance of the Lisbon treaty requirement that the EU should sign up to the European convention on human rights? When it gave its opinion on that, it said that it did not think it was compatible with the EU treaties, despite the fact that it had been signed up to in that particular treaty. Can something similar be done in this case to remove the uncertainty?