For Brits grappling with the idea of Scottish independence, it may be worth looking across the Atlantic.
In 1995, residents of Quebec voted on whether the province should separate from Canada. That referendum - narrowly won by the pro-Canada camp with just 50.6 percent of the vote - has an important lesson for Scots keen to end Scotland's 300-year union with England, and for the British establishment, which wants them to stay: the wording of the referendum question and the rules around it can help determine whether the country will stay in one piece.
It was very, very tense. It was our future. It was our national identity at stake, recalls Anglophone Quebec native Pauline Morasse, 58, who said she and her francophone husband Bernard have deep attachments both to Quebec and Canada.
We're both Quebecois and Canadian, and to have to sever one of those identities would have been like a divorce, she said. When the 'no' side finally won, she said she felt relief, almost disbelieving that we had come that close...to rupture.
Rattled by the close result, the Canadian government passed what it called the Clarity Act, which says Canada can only be broken up if a clear majority of voters - an undefined level but well over half - answers a clearly stated question in the affirmative.
It's a huge decision, said Stephane Dion, a political scientist recruited into cabinet after the referendum to draft the new legislation.
It's not a decision to choose a government, where you may change your mind five years later, he said. No, for a referendum about belonging to a country, you're voting in some ways for your children, your grandchildren and the next generations. So it's very important that clarity is protected under these circumstances.
DUTY TO BE FREE
In Britain, the rules of the debate are already in dispute. Prime Minister David Cameron and Scottish nationalist leader Alex Salmond have duelled over both the terms and timing of a referendum.
As in Canada in 1995, the debate is filled with hard-nosed economic and political calculations over how debt would be divided and what currency would be used, and passionate deliberation about splitting families and losing passports.
Salmond says separation would enable Scotland, with its North Sea oil, to become a wealthier and fairer nation. The Quebec separatists used a slogan that said everything would be possible economically upon separation. They came up with a formula that would have left them with just 17 or 18 percent of the federal debt, not the 25 percent that represented Quebec's share of the population; and they said they would continue to use the Canadian dollar - though Canada would have denied them a say in setting monetary policy.
These are also issues Scotland and London will have to work out. Bernard Landry, who as deputy Quebec premier in 1995 helped prepare for independence, sees a strong parallel between Scotland and Quebec. It's not the same case, but the fundamentals are the same. Scotland is a nation. Quebec is a nation, he told Reuters.
A nation when it's possible has the duty to be free, and that applies to Quebec and to Scotland, said Landry, who went on to become premier and now teaches at the Universite du Quebec a Montreal.
The biggest difference between the two cases is that Quebec's separatists were - and are - driven by language. French is the native language of four of five Quebec residents, whereas Gaelic is spoken by only about 1 percent of Scots.
Another difference is historic: Quebec, colonized by France in the 16th and 17th centuries, was conquered by Britain in 1760. Quebec and Canada are both creations of empire. Scotland, on the other hand, shared its monarch with England for most of the 1600s, and formed its union with the south in 1707 peacefully, even if many Scots opposed it.
Landry said he has long been interested in the Scottish question and had met Salmond many times over the years.
He spent much of the year prior to the 1995 referendum asking diplomats for recognition of Quebec in the event of a 'yes' vote. Most South American and French-speaking African countries told him they would recognize Quebec, he said, so we were not anxious at all.
The Quebec premier of the day, separatist Jacques Parizeau, made elaborate economic and political preparations, and reportedly told diplomats that Quebeckers would be like lobsters in a pot of boiling water if he got a majority.
He denied making the remark but later conceded that a unilateral declaration of independence was ready if he had won the referendum.
LET SLEEPING DOGS LIE?
Dion said a unilateral breakaway would have caused an extraordinary mess for a prolonged period, and even an agreed secession would have been complex. As it was, the Canadian dollar fell in the run-up to the October 30 vote, forcing the Bank of Canada to intervene repeatedly. Bonds and stocks also took a pounding.
Then-Prime Minister Jean Chretien felt he had been reduced to a helpless bystander. In the months that followed the referendum, he decided to clarify the process. He brought in Dion, who wrote open letters to the separatists, challenging their claims to an easy route to independence and arguing that if Canada was divisible, then Quebec was too and parts of it could decide to stay in Canada.
During the referendum, in fact, native groups in the vast north of the province, site of the huge James Bay hydroelectric complex, had said that if Quebec left Canada they would want their chunk of the province to stay. There was also talk that Quebec's business centre of Montreal might try to stay in Canada.
Dion asked the country's Supreme Court if Quebec had a right to self-determination and to declare independence unilaterally. The Court decided there was no such right but a clear vote for self-determination would oblige Canada to enter negotiations - even if these talks might not get far.
The bottom line from the court was that there had to be a clear majority on a clear question for anything to happen; Dion used this as the basis of the Clarity Act.
There was strong pushback within the federal cabinet to the idea. If you believe in Canada you don't like to contemplate its breakup, recalled Dion, a bespectacled man who looks more like an academic than a politician.
'Don't go there ... Let sleeping dogs lie' - these kinds of things were everywhere, and Mr. Chretien said very strongly, 'I will not allow another mess like this one. We need to clarify the issue for the sake of everyone.'
HOW TO POP THE QUESTION
Crucial to clarity, the court decided, is the wording of any referendum question. The 1995 question - which asked if voters agreed Quebec should become sovereign having offered Canada a new economic and political partnership - was complicated. Dion said some polls showed that one quarter of respondents mistakenly thought they could vote 'yes' and still stay in Canada.
CROP, a Quebec-based polling company, says the question can make a huge difference, particularly if the question contains a reassuring reference to keeping ties with the original country. The separatist camp (in Quebec) is at 40 percent if it's a straight question, CROP pollster Youri Rivest said. To get more than 50 percent of the voters they have to put some Canada in their offer.
The question that Salmond wants to pose is much simpler than the Quebec one: Do you agree that Scotland should be an independent country?
But critics, including some politicians in the British parliament, argue even that question could boost support for independence by as much as 10 points over one that asked if Scotland should leave the United Kingdom.
Salmond has also mulled asking voters if they want a more autonomous Scotland that would remain within Britain - so-called maximum devolution.
Dion said he did not want to give advice to Britain, but if it were in Canada he would not want an extra question. If you mix it with other issues, you make it less clear.
BARE MAJORITY ENOUGH?
As important as the wording of the question is the majority. Landry says a simple majority should be enough: Democracy is democracy. We lost at almost 50, and we accept the result. They will have to do the same.
But Chretien regularly said in public that he would not break up the country on the basis of a narrow simple majority - perhaps because some potential voter in favour of unity had forgotten his glasses. Quebec hunting clubs and labour unions required much stronger majorities, he said, so why shouldn't Canada?
Neither the Supreme Court decision nor the Clarity Act defined a clear majority, leaving it to the Canadian House of Commons - not Quebec's provincial government - to decide.
One risk of imposing national standards on secessionists - on how to set the question, for example - is that this might push undecided voters across the fence, to rally around the flag, said Universite de Montreal political scientist Pierre Martin, who has written extensively on the sovereignty movement.
Another drawback is that Canada's federal government has agreed the country is divisible, and laid out a road-map for how to secede. The United States, France, Spain and other big countries treat their countries as indivisible no matter what.
In Canada, we came to another conclusion, and it's part of our political culture, said Dion. We are very comfortable with this circumstance where, facing a clear result, a negotiation would start, he said.
But this being said I'm very convinced that with clarity Quebec will always choose to stay Canadian.
(Edited by Simon Robinson, Martin Howell and Sara Ledwith)