---

European Union Bill

That is not entirely fair. When Lord Kerr presented his argument, he suggested that referendums could be triggered on what are universally considered as fairly technical, minor matters. It is a hypothetical situation. Nevertheless, it is important to recognise that in the minutiae of negotiations, we negotiate effectively for the United Kingdom only when we do not have it in the back of our minds that there might be hurdles to be overcome at a later stage. The other two arguments used in the other place were essentially constitutional. It was argued that the referendums envisaged in the Bill are essentially post-legislative. In other words, once the Government have negotiated a treaty change and Parliament has agreed to it, a referendum will be held. As the referendum is post-legislative, it is a lock. The electorate will have to decide whether to overrule the Government and Parliament of the day. Holding referendums post-legislatively in that way questions Parliament's traditional role. Such a change should therefore be subject to constant review and reaffirmation or otherwise. That constitutional argument is worthy of consideration. By far the most important and powerful argument concerns the principle that a Parliament cannot bind its successor. That is a vital principle of our parliamentary democracy. In the evidence taken by the European Scrutiny Committee, which is ably chaired by the hon. Member for Stone (Mr Cash), a number of expert witnesses explained the importance of that principle. Michael Dougan, the dean of the Liverpool law school and a professor of European law at the university of Liverpool, concluded his evidence by saying:"““If there is a real concern about the doctrine of Parliamentary sovereignty that needs to be addressed during the passage of this Bill, it surely consists in an attempt by the Government to persuade the current Parliament to bind its successors in a manner which runs counter to accepted understandings of our constitutional order.””" That is a pretty powerful statement.