U.K.’s Historic ‘Brexit’ Referendum on a Knife’s Edge

With over a third of votes counted, Britain’s referendum on the E.U. was still too close to call early Friday morning, with the growing possibility of a ‘Brexit’ sending the pound plummeting to a five-month low.

Voters in rural England have overwhelmingly voted to leave the 28-nation economic bloc, with higher-than-expected margins of victory in the midlands and the north-east. Voters in Scotland and in London are backing Remain, but by generally smaller numbers. Wales too has sided with Leave.

Aaron Banks, co-founder of the Leave.EU grassroots campaign, said he thought his side would steal victory in the final count. “I think we will just edge it,” he told TIME early Friday morning. “50/50 is an epic result if you think what the British establishment has thrown at us, from Treasury warnings to Third World War. 50/50 is a massive defeat to Cameron even if he edges it.”

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The sterling slid dramatically against the dollar on the early U.K. results, falling to a five-month low at 3:45am local time as the market grew more convinced of a Leave victory. Asian stocks were volatile after the Nikkei opened.

With Leave seeming more likely to head towards victory, the future of Prime Minister David Cameron looked cloudy. Although 86 MPs signed a letter Thursday night urging him to stay in office regardless of the result, he would likely be blamed for the Remain campaign’s loss. If he were to stand down, some MPs would not rule out another vote. “A new general election is not impossible,” pro-Brexit Conservative MP Jacob Rees-Mogg told the BBC.

Exactly how Britain would withdraw from the E.U. would likely be a topic of huge debate. Article 50 of the Lisbon Treaty allow for two years of negotiations on the terms of exit, but they need to be approved by all 27 of the remaining member states. Only then would Britain be allowed to renegotiate trade agreements with the bloc.

Additional reporting by Tara John in London