Dr Julian Lewis: How can any negotiator achieve any concession from any other negotiator if it is known in advance that he will not walk away if no concessions are given?

[The Secretary of State for Exiting the European Union (Mr David Davis): My right hon. Friend is absolutely right. He crystallises the point on “no deal is better than a bad deal”, and he clearly demonstrates why the Labour proposal, apart from being completely impractical, would never be deliverable.]