The noble Lord, Lord Pannick, and the noble and learned Lord, Lord Judge, have helpfully identified a problem with the Bill, in that a counterproposal by the EU could fall between the cracks and result in an accidental no deal, thus frustrating the will of Parliament, in so far as that will is ascertainable.
In the event of a counterproposal, which seems likely, the amendment suggests that the Prime Minister has the power to seek or agree an extension to a date not earlier than 22 May. At col. 337, the noble Lord, Lord Pannick, suggested that approval would still have to be sought for that new date.
I wholly understand the thinking behind the amendment, but the apparent need for it underlines the strange constitutional waters in which we are now swimming. My understanding of the Gina Miller case is that the Government argued that Article 50 could be triggered without parliamentary involvement, whereas the opposing argument, advanced by the noble Lord among others, was that Parliament had legislated in such a way that the royal prerogative was enough on its own and that Parliament need not be involved. By a majority this argument prevailed, although there were three dissenting speeches.
The prerogative, however, allows Ministers, and in this case the Prime Minister, to make or unmake treaties unless Parliament has legislated to restrict that power. It rarely does, hence the paucity of useful precedents in the Gina Miller case. It seems to me that the Prime Minister would be allowed to agree a counterproposal as a matter of law. Whether that would be politically sound is a different matter.
The response of the noble Lord, Lord Pannick, is that it is or might be uncertain, but it seems to me that this amendment in fact fetters the royal prerogative. We have a dualist system of law in this country, which has worked well, and I wonder if it is wise to undermine the royal prerogative in this way. To make a constitutional change of this sort needs prolonged and serious thought. A Private Member’s Bill that went through all its stages in the House of Commons in four hours, that was not given pre-legislative scrutiny and that, for good reasons, is hurrying through this House, is surely not the context in which to make significant constitutional changes.