A European Union (EU) flag, left, and a British Union Flag, also know as a Union Jack, stand at a foreign exchange brokerage in Tokyo, Japan, on Friday, June 24, 2016. The pound tumbled with the euro and U.K. equity index futures after early results from Britain's referendum on membership of the European Union put the "Leave" campaign ahead, suggesting the risk of a so-called Brexit is greater than opinion polls implied. Photographer: Tomohiro Ohsumi/Bloomberg via Getty Images
