Caroline Lucas has alluded to the Adjournment debate that I had a few weeks ago on this issue of the conditional interpretative declaration, which I have been pressing the Government to use for some time. Can my right hon. Friend confirm that, under international law, such an interpretative declaration does indeed have the full force of international law, it is legally enforceable, it has exactly the same weight as the withdrawal agreement and the advantage of it is that it allows us to make a statement that the backstop is indeed temporary, or has a time limit, and it is now up to the EU if we have made such an interpretative declaration to refuse to ratify the treaty? A mere protest is not good enough, so this has full legal force. It is a very useful instrument and the House should pay the closest attention to it.