I was addressing the lack of clarity and clear guidance in the EU Treaty (as amended and consolidated in the Treaty of Lisbon, particularly Article 50). I can only assume that as it was written by the EU it was vague by design. PM Brown did not sign it but gave Milliband the pen. Maybe Gordon knew something spooky?
Anyway the Lisbon Treaty is separate to but resulted in this Withdrawal Agreement, which itself is as bad, or worse. The Belfast Agreement itself, is also separate, of course.