Theresa May has won the battle to be Britain's prime minister but she will face a much tougher struggle once in power — overseeing her country's divorce from the European Union.

May backed the "Remain" camp during the campaign for Britain's referendum on EU membership on June 23 but has made clear since then that it must now go ahead, saying, "Brexit means Brexit."

But she has also said Britain should not trigger the exit proceedings until London is ready to start negotiations.