London: British Prime Minister David Cameron last night announced his resignation from office, saying he was no longer the right person to lead the country after Britain voted, against his wishes, to leave the European Union.
However, Mr Cameron said he would stay in the role until the Conservative Party conference in October, to ensure stability, after the shock referendum result that defied late polls and was predicted to hurt the global economy.
Only then would his successor invoke Article 50 of the Treaty of Lisbon to trigger the exit process itself.
His announcement outside 10 Downing Street, accompanied by his wife, came at the end of an extraordinary series of events, which saw Nigel Farage, leader of the UK Independence Party and for years the face of British separatism, announcing the vote as Britain's "independence day".
A jubilant Mr Farage said it marked the beginning of the collapse of the "failed" European project, and the resurgence of a Europe of sovereign nation-states.
The Leave campaign won with 17.1 million votes to 16.4 million after 72 per cent of the electorate turned out to vote.
The rusting industrial, white working-class heart of Britain led a surge of votes for the island to break its legal and economic ties to Europe and reset itself as an independent nation. The vote to leave was also dramatically skewed to older people, with 64 per cent of 18 to 25-year-olds voting to stay.
Motivating the vote was mistrust of unchecked immigration from Europe, analysts said.
Free movement of labour is one of the pillars of the union. But Leave voters feared immigrants were overloading Britain's health, education and welfare systems, pushing wages down and house prices up.
The pound took a huge hammering, plunging 10 per cent to hit levels not seen since the 1980s, as the markets predicted trouble ahead for the British economy outside the EU trade zone, and ripple effects in Europe and beyond.
In Australia, the ASX 200 lost 167 points, or 3.2 per cent, wiping $50 billion off the value of the market, the worst day since the Chinese sharemarket meltdown in August. Around the world, Japanese shares tanked 7.7 per cent as the yen surged, but Chinese mainland shares only eased by less than 1 per cent. Hong Kong's Hang Seng fell 4.3 per cent.
Economists have predicted a recession in Britain would result from the vote.
But Prime Minister Malcolm Turnbull urged calm, noting, for domestic political consumption, that global turbulence showed the need in Australia for "strong economic leadership".
"We need to have a stable majority government with a clear economic plan, so we are resilient and able to deal with those unexpected events that occur, with those uncertainties that arise," Mr Turnbull said.
Australian defence and foreign affairs experts reacted with dismay, warning it will lead to a more fragmented West and make the world a less secure place.
They said the result would distract Britain from its usually reliable role as a security player, embolden Russia and possibly diminish Washington's "pivot" to Asia, with consequences for Australia's region.
Kerry Stokes, executive chairman Seven Group holdings, said the British had "decided to do what Australians have already decided to do, which is to protect our borders".
In Europe, the vote is already being called an earthquake in the politics, and economies, of Britain and the continent. Political unionists fear the end of the "European project", the status quo on the continent since World War II.
No country has ever left the EU, but Dutch far-right politician Geert Wilders immediately called for a referendum, and France's National Front leader Marine Le Pen, who will run for president next year, hailed the result.
The Leave camp said democracy would return to Westminster.
The favourite to take over from Mr Cameron is his arch-rival Boris Johnson, who is expected to push to lead a government that will activate, for the first time, the European treaty articles that lead to an exit from the union.
But Labour leader Jeremy Corbyn will also be under pressure, as Labour's northern heartland resoundingly rejected his plea to vote Remain.
Some political analysts were tipping an early election - despite recent laws that enshrined fixed parliamentary terms.
The vote saw unexpectedly high turnouts for Leave in Britain's north, where disaffected working-class communities are suspicious of immigration and felt modern politics and economics had failed them.
The regions generally plumped for Leave, and although London was a bastion for Remain, the turnout there might have been suppressed by torrential rain, which caused public transport chaos and saw some polling places closed or moved.
Scotland voted strongly to Remain, but turnout was much weaker than had been expected.
Scottish National Party politicians have foreshadowed the nation may push again to secede from Britain, in order to stay in Europe.
Northern Ireland also came down on the Remain side, due to fears of the effect that Brexit would have on the border with the Republic of Ireland.
Chancellor of the Exchequer George Osborne has said he might have to bring down an emergency budget to deal with the vote's aftermath.
Labour's shadow chancellor John Macdonnell predicted the Bank of England would have to intervene to slow the fall of the pound.
He said the market might be reassured if the government promised to bargain for the best trade deal it could get with Europe, from the outside.
The EU's leaders in Brussels are expected to play hardball in negotiating Britain's exit, to send a message to other states that might be contemplating a similar move.
Informal meeting of EU 27 next week without PM in the room to decide common negotiating position vs UK on exit negotiations— Faisal Islam (@faisalislam) June 24, 2016
The result was another terrible night for pollsters and bookies, almost all of whom had predicted a narrow Remain win.
They had also failed to predict last year's general election win for the Conservatives.
Polling also caused Mr Farage to concede a likely Remain victory even before a single vote had been counted. He later "unconceded".
At 4am, before an official or media call of the result, he claimed victory.
"The dawn is breaking on an independent United Kingdom," he said. "This will be a victory for real people, a victory for ordinary people, a victory for decent people.
"Honesty, decency, the belief in nation I think now is going to win."
The campaign was won by "damn hard work on the ground", he said.
"I hope this victory brings down this failed project and leads to a Europe of sovereign nation-states.
"Let June 23 go down in history as our independence day."
Matthew Goodwin, politics professor at the University of Kent, said the referendum had exposed a sharp divide in British society. It had shown there were social groups with very different values. The Leave vote was a "very loud and very clear message" that the EU and globalisation were not benefiting them and that Westminster elites were not listening to them, he said.
Sara Hobolt, professor at the London School of Economics, said the referendum had given the disaffected and disenfranchised a chance to stick it to the political class.
The Leave campaign had cleverly played the "people versus the elite" card, she said.
Some voted on the EU, some on the economy, some on immigration.
It came down to a question of whether people were more scared of uncapped immigration or of the potential economic chaos following Brexit.
The referendum result has no legal power, but the government is expected to respect the result and begin the Brexit process.
More than 46 million people were registered to vote in the third nationwide referendum in British history.
With Michael Bachelard, David Wroe, Nassim Khadem
