But her claims rang hollow for Mr Howe, a specialist in EU law who let loose in a caustic column for The Sun. He wrote: “Politicians who claim this is just a bad treaty – one we can get out of later – are being ignorant or disingenuous.”

With respect to the backstop for Northern Ireland, for example, he said once it was in force, the UK would not be able to leave it without a joint decision with the EU which he said amounted to a veto over the UK’s exit.