Europe demands quick divorce from divided Britain

With characteristic caution, German Chancellor Angela Merkel said only that Britain's exit talks should not "drag on forever" and that until they were completed, Britain would remain a fully-fledged EU member.

"There is no reason to be nasty in the negotiations. We have to follow the rules of the game," she said.

Earlier, European Commission chief Jean-Claude Juncker warned London against foot-dragging. "It is not an amicable divorce but it was also not an intimate love affair," he said.

The British vote has stoked fears of a domino-effect of exit votes in eurosceptic member states that could imperil the integrity of the bloc.

In an early sign of the Brexit fallout in Brussels, Britain's European commissioner for financial services, Jonathan Hill, said he would stand down.

"I don't believe it is right that I should carry on as the British commissioner as though nothing had happened," he said.

At home, more than two million Britons signed up to a rapidly-growing petition on an official government website pleading for a new vote.

"I am worried, really sick for my children's prospects," said Lindsey Brett, a 57-year-old secretarial worker.

"I was expecting a 'Remain' vote. I did not think we would come out," she said in central London.

The number of signatories far surpassed the 100,000 required for a proposal to be discussed in the House of Commons. A committee will consider the motion on Tuesday.

Scotland in particular stood aghast at the prospect of being dragged out of the 28-nation European Union when more than 60 percent of its people voted to stay in.

First Minister and Scottish National Party leader Nicola Sturgeon said the country was seeking "immediate discussions" with its EU partners to try to protect its position in the bloc.

"A second independence referendum is clearly an option that requires to be on the table," she said after an emergency cabinet meeting, where ministers agreed to start drawing up legislation that could enable a second vote.

Scots backed staying in Britain in their last referendum in 2014. It is unclear how the EU referendum may have changed that position.

The often poisonous EU campaign revealed a split between what The Independent newspaper called "those doing well from globalisation and those 'left behind' and not seeing the benefits in jobs or wages".

Opposition Labour leader Jeremy Corbyn is facing calls to resign over a perceived lacklustre campaign to stay in the EU, which resulted in many Labour voters choosing to leave.

"It's your fault, Jeremy. When are you resigning?" shouted one party activist as Corbyn attended Gay Pride in London.

Young people, graduates, and big cities tended to favour "Remain". Elder, less educated people and rural populations were more likely to back "Brexit".

"I feel angry. Those who voted leave, they're not going to fight the future," said Mary Treinen, 23, a technological consultant from London's trendy Shoreditch district.

Britain's rejection of the EU is being seen as a victory for the anti-establishment rhetoric of the Brexit campaign, a feature of growing populism across Europe.

Dutch far-right MP Geert Wilders and French National Front leader Marine Le Pen immediately called for referendums on EU membership in their own countries.

"Take a bow, Britain!" eurosceptic newspaper the Daily Mail wrote across its front page on Saturday.

"It was the day the quiet people of Britain rose up against an arrogant, out-of-touch political class and a contemptuous Brussels elite," it added.