The prime minister David Cameron announced this morning that he is to resign after the UK became the first country since the Lisbon Treaty was signed to leave the EU.
At just before 4.45am the BBC called the result of the historic referendum: a Leave vote, which will sever Britain’s 43-year membership of the economic bloc.
In his resignation speech, Cameron said Britain required "fresh leadership" to negotiate the country's exit from the EU.
"I do not think it would be right for me to be the captain that steers our country to its next destination," he said in a statement outside Downing Street.
He promised to "steady the ship" over the coming months before stepping down in October.
Markets were generally unprepared for a Leave result after the last opinion polls, and the bookies, before the vote had pointed to a victory for the Remain camp.
The pound fell to its lowest level against the dollar since 1985 as the markets reacted to the results.
Stock markets globally are suffering huge sell offs after the UK voted to leave the EU. The Leave vote caught many traders off guard. The pound’s swing of more than 10% against the dollar is its biggest intraday move since at least 1989.
In the opening minutes of trade, the FTSE 100 index fell more than 500 points. Banks were hit hard, with Barclays and RBS shares falling around 30%.
In a bid to calm the markets, Bank of England governor Mark Carney in a speech warned that, "economic volatility can be expected as this process unfolds".
But he would "ensure that the UK financial system can absorb any stresses and can do its job of concentrating on serving the real economy." He added that the economy will “adjust to new trading relationships that will be put in place over time.”
He also pledged to provide £250bn of funds to calm the situation.
The Financial Conduct Authority (FCA) said much financial regulation currently applicable in the UK derives from EU legislation. This regulation will remain applicable until any changes are made.
It added in a statement, “Firms must continue to abide by their obligations under UK law, including those derived from EU law and continue with implementation plans for legislation that is still to come into effect.
“Consumers’ rights and protections, including any derived from EU legislation, are unaffected by the result of the referendum and will remain unchanged unless and until the government changes the applicable legislation.”
Donald Tusk, president of the European Council, said the 27 remaining members will meet to assess its future next week without Britain. Tusk said he had spoken to EU leaders in the past few days and the union had been prepared for the result and was determined to keep its unity.
Jeremy Corbyn, the Labour leader, called for Article 50 of the Treaty of Lisbon – the clause that allows the UK to leave the European Union – to be invoked straight away. He told the BBC, “Many communities are fed up with cuts and economic dislocation and feel very angry about the way they have been betrayed and marginalised. My point was we had to have an alternative to austerity and greater resources going into areas where there have been huge changes.”
Ukip leader Nigel Farage said 23 June will "go down in history as our independence day". Farage was heavily criticised last week for using a poster to promote the Leave campaign, which depicted a snaking line of hundreds of immigrants arriving in Europe, that critics described as racist. He refused to apologise.