EDINBURGH, Scotland (AP) — Excitement vied with apprehension as Scottish voters went to the polls Thursday in a referendum on independence, deciding whether to dissolve a 307-year union with England that brought prosperity but has increasingly felt stifling to many Scots.

As the polls closed and the vote counting began, there was a quiet thrill of history in the making on the fog-shrouded streets of Scotland's capital, Edinburgh. Many Scots were staying up all night in homes and bars to watch the results roll in.

Eager voters had lined up outside some polling stations even before they opened at 7 a.m. Many polling stations were busy and turnout was expected to be high. More than 4.2 million people had registered to vote — 97 percent of those eligible — including residents as young as 16.

A Yes vote would trigger 18 months of negotiations between Scottish leaders and London-based politicians on how the two countries would separate their institutions before Scotland's planned Independence Day on March 24, 2016.

For some, it was a day they had dreamed of for decades. For others, the time had finally come to make up their minds about the future — both for themselves and for the United Kingdom.

"Fifty years I fought for this," said 83-year-old Isabelle Smith, a Yes supporter in Edinburgh's maritime district of Newhaven, a former fishing port. "And we are going to win. I can feel it in my bones."

For Smith, who went to the polling station decked out in a blue-and-white pro-independence shirt and rosette, statehood for Scotland was a dream nurtured during three decades living in the U.S. with her late husband.

"The one thing America has that the Scots don't have is confidence," said Smith, who returned to Scotland years ago. "But they're getting it, they're walking tall."

"No matter what, Scotland will never, ever be the same again."

The question on the ballot paper could not be simpler: "Should Scotland be an independent country?"

Yet it has divided Scots during months of campaigning, generating an unprecedented volume and intensity of public debate and participation. The Yes side, in particular, has energized young people and previously disillusioned working-class voters.

Polls suggest the result was too close to call. A final Ipsos MORI poll released Thursday put support for the No side at 53 percent and Yes at 47 percent. The phone survey of 991 people has a margin of error of plus or minus three percentage points.

Until recently, polls suggested as many as 1 in 5 voters was undecided, but that number has shrunk dramatically. In the latest poll, only 4 percent remained uncertain how they would vote.

Many questions — the currency independent Scotland would use, its status within the European Union and NATO, the fate of Britain's nuclear-armed submarines, based at a Scottish port — remain uncertain or disputed after months of campaigning.

After weeks in which British media have talked of little else, the television airwaves were almost a referendum-free zone Thursday. Electoral rules forbid discussion and analysis of elections on television while the polls are open.

On the streets, it was a different story, with rival Yes and No billboards and campaigners outside many polling places.

At an Edinburgh polling station, Thomas Roberts said he had voted Yes because he felt optimistic about Scotland's future as an independent country.

"Why not roll the dice for once?" he asked.

Once the polls closed, ballot boxes were to be transported to 32 regional centers for counting. The result was expected Friday morning.

Roberts said he was looking forward to learning the outcome in a pub, many of which were staying open overnight.

"I'm going to sit with a beer in my hand watching the results coming in," Roberts said.

Many who oppose independence agreed that the campaign had reinvigorated Scottish democracy.

"I support the No side, but it's been a fascinating, worthwhile discussion about Scotland's future," said David Clarke, a writing consultant.

"If it's a No, it's a win-win situation. If it's a Yes, we will have to deal with the fact that it's a Yes."

But other No supporters said the noisy pro-independence campaign had divided the country and fueled bad feeling among neighbors.

"The country is divided with a hatchet. It's so awful — and it was completely unnecessary," said Fiona Mitchell, distributing No leaflets outside a polling station.

First Minister Alex Salmond, leader of the independence campaign, cast his vote near his home in northeastern Scotland. If the Yes side prevails, he will have realized a long-held dream of leading his country to independence from an alliance with England formed in 1707.

In a final speech on Wednesday night, Salmond told voters: "This is our opportunity of a lifetime and we must seize it with both hands."

Pro-independence forces got a last-minute boost from tennis star Andy Murray, who signaled his support of the Yes campaign in a tweet to his 2.7 million followers early Thursday.

Anti-independence leaders, including former Prime Minister Gordon Brown, have implored Scots not to break their links with the rest of the United Kingdom, and have stressed the economic uncertainties independence would bring.

Many Yes supporters planned to stay up late in bars, or to gather in symbolic spots like Calton Hill, overlooking Edinburgh — hoping the sun will rise Friday on a new dawn and not a hangover.

But financial consultant Michael MacPhee, a No voter, said he would observe the returns coming in "with anxiety."

Scottish independence was "the daftest idea I've ever heard," he said.

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Follow Jill Lawless on Twitter at http://Twitter.com/JillLawless