When historians come to write the tale of Britain’s attempts to leave the European Union, this week may be seen as the moment the country finally grasped the mess it was in. Parliament was so scornful of the exit deal that Theresa May had spent two years negotiating in Brussels that MPs threw it out for a second time, in the fourth-biggest government defeat in modern parliamentary history. Then they rejected what had once been her back-up plan of simply walking out without a deal. The prime minister has lost control. Cabinet ministers are defying her and both main parties are splintering into ever-angrier sub-factions. And all this just two weeks before exit day. The chaos demands something better. Our cover this week sets out what that should be