Scotland has started voting in a referendum to choose whether to end the 307-year-old union with England and become an independent nation or stay within the United Kingdom – a decision which could have consequences outside Britain.

As polls open in Scotland, most opinion polls and experts say it is a vote too tight to predict. The voting is going to continue until 21 GMT on Thursday.

In its final hours, the battle for Scotland had all the trappings of a normal election campaign: “Yes Scotland” and “No, Thanks” posters in windows, buttons on jackets, leaflets on street corners and megaphone-topped campaign cars cruising the streets blasting out Scottish songs and “Children of the Revolution.”

The gravity of the imminent decision was hitting home for many voters as political leaders made passionate, final pleas for their sides.

The independence movement says Scots should be able to choose their own leaders and make their own decisions rather than be ruled from London. Many of those voting for independence felt that being governed from the Westminster parliament had opened too wide a gap between rich and poor.

The prospect of breaking up the United Kingdom, the world’s sixth-largest economy and a permanent member of the United Nations Security Council, has prompted citizens and allies alike to question what would be left.

British politicians, banks and businessmen have closed ranks to warn of economic hardship, job losses and investment flight should Scots decide to go it alone. Defence would also be a big question – Britain’s submarine-borne nuclear arsenal, part of NATO’s defences – is based in Scotland’s Firth of Clyde.

European leaders have warned that an independent Scotland would have to get to the back of the queue to join the European Union. Spain has been especially vocal, fearing it would further inspire separatists in Catalonia and the Basque Country,

The United States has made clear it wants the United Kingdom, its main ally in Europe, to remain together.

More than 4.2 million people are registered to vote in the country of 5.3 million people. including, for the first time, 16 and 17-year-olds – with neither side assured of a victory.

The latest polls released by Ipsos MORI, on Wednesday, put opposition to independence at 51 percent and support at 49 percent, with five percent of voters undecided. The company had conducted a telephonic poll of 1,373 people.

Gordon Brown, former British prime minister, who is himself a Scot, told a “No” campaign rally that the quiet majority of pro-Union Scots “will be silent no more”, while Alex Salmond, pro-independence leader and Scottish first minister, urged voters to seize a democratic opportunity 307 years in the making.

‘Independence within reach’

Cathy Chance, who works for Britain’s National Health Service in the Scottish capital, Edinburgh, said she would leave Scotland if it became independent.

“I don’t want to live under a nation that’s nationalistic,” she said. ” I don’t think the world needs another political barrier.”

On the other side, “Yes” campaigner Roisin McLaren said she was finally letting herself believe independence might be possible.

“My family has campaigned for independence for a long, long time, and it’s always been a pipe dream,” the Edinburgh University student said as she knocked on doors in a last-minute effort to convert wavering electors.

“Just in the last few days it’s seemed possible, within reach. I can almost taste it.”

A “Yes” vote would trigger months of negotiations between Scotland and the British government over the messy details of independence, which Scottish authorities say will take effect on March 24, 2016, the anniversary of the date in 1707 that Scotland decided to unite with Britain. Al Jazeera