Theresa May will take the high-stakes battle to save her Brexit plan and her premiership to all four nations of the United Kingdom this week. The prime minister will warn MPs in Westminster on Monday that failing to back the deal will take Britain “back to square one”.

EU leaders gave their formal backing to the Brexit deal at a special summit in Brussels on Sunday, after more than a year and a half of painstaking negotiations. But they were adamant that there was no plan B other than a no-deal exit if MPs were to reject it in the House of Commons in a “meaningful vote” planned to take place before Christmas.