Scotland's pro-independence leader Alex Salmond said Friday he would resign after losing a referendum that left the United Kingdom intact but opened a Pandora's box of demands for more autonomy across Britain.

Despite a surge in Scottish nationalist support in the final fortnight of the campaign, the anti-independence "No" camp secured 55.30 percent of the vote against 44.70 percent for the separatist "Yes" side.

After a campaign that fired up break-away movements around the world and stoked political passions across the United Kingdom, turnout was 84.6 percent -- the highest ever for an election in Britain.

"No" campaigners across Scotland cheered, hugged and danced as the results came in the early morning.

British Prime Minister David Cameron said he was "delighted". He declared that the referendum had produced a "clear result", and added: "Now the debate has been settled for a generation."

Scottish First Minister Alex Salmond conceded defeat and said he would be stepping down from his post and from the leadership of his Scottish National Party (SNP) at its conference in November.

"For me as leader, my time is nearly over. But for Scotland the campaign continues and the dream shall never die," he said at a press conference in Edinburgh.

Many "Yes" activists had watched the result in tears, although Salmond urged them to take heart from the huge number -- 1.6 million -- who backed independence.

"We lost the referendum vote but Scotland can still carry the political initiative," he said, adding that "the party, parliament and country would benefit from new leadership".

The result reassured investors worried about the economic risks of a break-up and the pound reached a two-year high against the euro while European stock markets rallied.

The CBI lobby group said the result would be greeted by a "collective sigh of relief across the business community", while the Scotch Whisky Association urged "politicians of all parties to work to bring our country together".

There was also relief in many European capitals, where a "Yes" vote would have given unwanted encouragement to separatist movements from Flanders in Belgium to Catalonia in Spain.

US President Barack Obama said he hoped to continue his country's "strong and special relationship with all the people of Great Britain and Northern Ireland".

'Scotland gains almost everything'

A "Yes" vote would have brought to an abrupt end a union between Scotland and England stretching back to 1707. But while the UK survived, it could soon look very different.

The British government must now deliver on promises made in the heat of the campaign to give more powers over tax, spending and welfare to the devolved government in Edinburgh.

Cameron stood by the pledge on Friday, under which "Scotland gains almost everything except for full independence", said Emily St Denny, a politics professor at Stirling University.

However, Salmond cast doubt on Cameron's ability to deliver, saying there were already signs that the tight timetable for implementation was slipping.

The prime minister also promised more local control for other parts of the UK, heading off growing demands from Conservatives and the UK Independence Party (UKIP) for England to be given more powers.

"Just as Scotland will vote separately in the Scottish parliament on their issues of tax, spending and welfare, so too England, as well as Wales and Northern Ireland, should be able to vote on these issues," he said.

In what would be a radical shake-up of the constitutional order, he said these new powers would be delivered at the "same pace" as the Scottish settlement, suggesting legislation would be drawn up as soon as January.

"We're moving towards a more federal version of Britain," Tony Travers, professor of politics at the London School of Economics (LSE), told AFP.

'Crushing, devastating result'

In Edinburgh, nationalists struggled with their emotions.

Charlotte Darroch, one of many 16- and 17-year-olds who were allowed to vote in a British election for the first time, said the result was "just crushing, quite devastating".

"I genuinely thought the feeling on the ground was different," said the 16-year-old, wearing a blue-and-white Scotland flag over her school uniform.

But Louise Fleming, 21, who also lives in the Scottish capital, said she was "relieved".

"We can't expect everything to be great tomorrow but the right outcome has occurred," she said.

Scotland's largest city Glasgow was among some big wins for the "Yes" campaign, but the margin was not enough to mitigate a flood of "No" votes across the country.

The indication was that better-off and rural areas had voted "No" while urban centres and poorer parts voted "Yes".

'Harry Potter' author and pro-union supporter J.K. Rowling, who is English but lives in Scotland, said Scots should be "proud", whatever their differences.

"Been up all night watching Scotland make history. A huge turnout, a peaceful democratic process: we should be proud."