The duty of good faith and to use best endeavours is a legally enforceable duty. There is no doubt that it is difficult to prove—[Interruption]—as I hear from a sedentary position, but that is not to say that it has not been proven. The case reports of the International Court of Justice, as well as arbitral tribunals throughout the world, have recorded decisions where tribunals have found breaches of good faith duties. There would need to be clear and convincing evidence that the breakdown of communication was due to bad faith—I fully accept that—but if the EU refused to engage with us, strung out negotiations in a thoroughly unreasonable way or failed to observe reasonable time limits, those would be hallmarks of a possible case of breach of good faith. It is a meaningful legal obligation.
I remind the House that we are dealing here with the United Kingdom on one hand and the European Union on the other. Their reputations in international forums, and their reputations as a question of international law, are at stake. If you put your name to a solemn legal obligation to negotiate something in good faith within a certain time limit, it is a very serious obligation of which to acquit yourself: it cannot just be played fast and loose with.