First mainland Brexit result closer than expected

The first mainland result declared in Britain's historic EU referendum on Thursday gave a very slender lead to the campaign to stay in the bloc, but was much closer than expected, an expert said.

Newcastle-upon-Tyne in the northeast of England voted "Remain" by 50.7 percent, with 49.3 percent backing "Leave", on a turnout of 68 percent.

"Wow. That could be a very big worry" for Prime Minister David Cameron's "Remain" side, Professor Simon Hix of the London School of Economics told reporters in London.

He said that under his projections, if the whole of Britain was split evenly, Newcastle should have voted "Remain" by a margin of 18 points.

Earlier, Gibraltar had been the first of the 382 local counting areas to declare, voting overwhelmingly in favour of staying in the EU, as had been expected.

The territory on Spain's southern tip voted 95.9 percent "Remain", against just 4.09 percent -- 823 votes -- for "Leave".