EDINBURGH: The campaign for Scotland's independence referendum went down to the wire on Wednesday ahead of a knife-edge vote that will either see Scotland break away from the United Kingdom or gain sweeping new powers.

The “Yes” and “No” camps mobilised thousands of volunteers to take to the streets across Scotland in a final push to win over undecided voters in a heated debate that has fired up Scots on both sides.

Three new opinion polls suggested a very narrow majority against independence but showed that the undecideds could swing it either way with just hours to go before polls open on Thursday at 0600 GMT.

“I'm really optimistic that if we do have independence, we can start building a society that works for all of us,” said 24-year-old Sam Hollick, a “Yes” activist from the Green Party who was campaigning at a stand in Edinburgh blaring a song by Scottish band The Proclaimers.

But at a “No” rally in Glasgow, former British prime minister Gordon Brown appealed to Scots' wartime patriotism and said voting against separation would still mean Scotland gaining much greater local power.

“We fought two world wars together,” he told hundreds of supporters.

“There's not a cemetery in Europe that doesn't have a Scot, a Welshman, an Irish and an Englishman side by side. When they fought together, they never asked each other where they came from,” he said.

'Cool heads'

Differences over whether to support “Yes” or “No” have divided families and lifelong friends and the Church of Scotland on Wednesday called for “a spirit of unity” and “cool heads and calm hearts”.

The rise in support for the “Yes” campaign has also sent jitters through the financial markets, helping to bring down the value of the pound and dragging down the stocks of Scotland-based companies.

Scotland's pro-independence First Minister Alex Salmond has dismissed the economic arguments, including what currency an independent Scotland would use as the Bank of England has ruled out a currency union, as “scaremongering” by the “No” campaign.

In a letter to the people of Scotland, Salmond urged the electorate to seize its historic chance to end the 307-year-old union with England.

“Wake up on Friday morning to the first day of a better country. Wake up knowing you did this, you made it happen,” Salmond wrote.

“It's about taking your country's future into your hands. Don't let this opportunity slip through our fingers. Don't let them tell us we can't. Let's do this. “

But Heather Whiteside, a 21-year-old graduate from Glasgow University who came to see Brown at a campaign event in the city said the prospect of a “Yes “victory was “very scary”.

“Nationalism is a bad kind of politics, it tries to create artificial barriers between people,” she said.

'Torpedo' for Europe

A “Yes” victory would not mean independence overnight but would sound the starting gun on months and possibly years of complex negotiations on separating two deeply linked economic systems.

It could lead to Prime Minister David Cameron's resignation and would embolden other separatist movements around the world.

Spanish Prime Minister Mariano Rajoy weighed in on the debate on Wednesday, branding moves for independence like Spain's Catalonia region a “torpedo” to European integration.

“Everyone in Europe thinks that these processes are hugely negative, “financially and economically, Rajoy told the Spanish parliament.

All three polls in Wednesday's papers showed that going it alone would be rejected by 52 percent to 48 percent, with undecided voters excluded.

But the results were within margins of error and many commentators have said the final outcome is “too close to call” ahead of time.

Record numbers have registered for the referendum, 97 per cent of eligible voters, and turnout is expected to be very high with officials saying it could be around 80 per cent.

In Edinburgh, Fatima Somner, a 45-year-old cashier of Moroccan origin married to an Englishman, said she was hoping for a “No” victory.

“People who will vote 'no' are the ones who have money. Poorer people are going to vote 'yes',” she said.

“They hope that things will change for the better for them. But it will be the opposite, everything will become more expensive! “But many said they were keen to make a final break with London.

“I've been ruled by Westminster governments for too long,” said Frank Evans, a 62-year-old in Glasgow at a “Yes” rally filled with flags, including one celebrating a famous Scottish victory over the English at the Battle of Bannockburn in the Wars of Independence in 1314.

“I am very confident. Yes, we'll win. I might be having a little bit of a dance in the city to celebrate,” he said. Behind him a banner read: “Break the chains, Scotland”.