EU Exit Could Cost U.K. $84 Billion Unless Borders Stay Open

Leaving the European Union could cost Britain 56 billion pounds ($84 billion) a year by 2030 unless the country keeps its borders open, according to a research group.

A report by Open Europe sets out four scenarios, based on Britain exiting the EU on Jan. 1, 2018. In the worst case, a hostile exit, gross domestic product would be 2.2 percent lower than if the U.K. had stayed in the EU. The best case, involving Britain reaching a free-trade deal with the rest of the EU and removing barriers to trade with the rest of the world, sees GDP increasing 1.6 percent. The best three scenarios require Britain to refrain from curbs on migration.