Despite the new information conveyed to policy-makers regarding the deeply integrated and connected nature of global trade organized within global value chains (GVCs) and coordinated by a few lead global firms, much of this seems neglected in the current debate on Brexit. The populist debate harks back to a far more mercantilist time, when the interests of nation states and domestic firms were far closer aligned than is the case today. Nowadays, most trade is in intermediate, not final, goods, with a large share being intra-firm. These new understandings of global trade, as well as the major information gaps revealed since the global financial crisis and the great recession, pose a major challenge to understanding the full implications of Brexit. Mercantilist-styled ‘beggar-thy-neighbor’ strategies can turn out to be ‘beggar thyself ’ miscalculations.