WHAT HAPPENS IF … IT'S A YES?
… to the currency?
The big unknown. Alex Salmond says Scotland would continue to use the pound, but the three main Westminster parties say they have no intention of allowing a currency union with an independent Scotland, which they say would be bad both for the rest of the UK and Scotland.
Another option for Salmond is "sterlingisation", under which Scotland would continue to use the pound without the backing of the Bank of England. Experts say this would be risky for Scotland's financial services industry, such as the Bank of England's role as lender of last resort. Scotland could join the euro, if it is admitted into the EU as a separate state, but Salmond has said this is not on the cards. And the Scots would have to meet strict convergence criteria, including on debt and deficit - difficult in a period of instability followed by a yes vote.
… to the 2015 UK election?
The general election is set for 7 May 2015, but what would be the position of the 59 Scottish MPs, if Scotland had by then said yes to independence? The answer could well have a bearing on which party has more seats at Westminster and forms a government.
Some Tory MPs say the election should be postponed for a year until Scotland is actually independent and would take no part. The target date for declaring independence is 24 March 2016.
Most constitutional experts think that, given the introduction of fixed-term parliaments, it would be hard to postpone an election. The consensus seems to be that Scottish MPs should stand in 2015 and remain until independence, representing areas still in the UK until March 2016.
The House of Lords committee on the constitution said it recognised that Scottish MPs staying until spring 2016 would be controversial, particularly if they still voted on issues relating to the rest of the UK, and/or on those affecting the UK after Scotland's independence.
… to Scotland and the EU?
Alex Salmond has suggested that Scotland will be able to remain part of the EU once independent, becoming its 29th member state, and that it will not have to reapply. It can, he says, agree its terms of membership "from within".
This is not how Brussels sees it. José Manuel Barroso, the outgoing president of the European Commission, made it clear earlier this year that Scotland would have to leave and reapply. He also said that the process would not be easy, not least because all 28 existing countries would have to agree. One problem could well be Spain, which is worried about Catalan independence and does not want to encourage those promoting it to think that they too could make an easy transition to separate EU membership. Some in Brussels say it could take five years for Scotland to meet all the conditions, particularly if it suffers currency instability having left the UK.
… to Trident?
The SNP says Trident, currently housed at the Faslane naval base, should be removed from an independent Scotland by 2020 as part of its plans for a constitutional prohibition on nuclear weapons being sited in the country.
Faslane would become the base for the Scottish navy, which would allow for many of the 6,500 jobs there to be maintained.
The precise future of Trident, however, is bound to be one of the most keenly contested issues in negotiations that would follow a yes vote.
Although the SNP would have a mandate to banish it from its shores, there are arguments about the feasibility and cost of moving it to another UK location within the four-year time frame envisaged. Negotiations over who would pay for it to be moved would also be difficult.
… to David Cameron and Labour?
A yes would be a disaster for both the Tories and Labour, but in very different ways. The Tories have always prided themselves on the being the party of the union, despite their dwindling support north of the border in recent years.
For David Cameron to be the prime minister who presided over its break-up of the union would be a humiliation. Although he has made clear he would not resign, his authority would be weakened. With the UK facing an in/out referendum on EU membership, Cameron could be the PM who leads us out of the union and out of the EU. But there would be an upside for Tories - the nightmare consequence of a yes vote for Labour.
An independent Scotland would massively hit Labour's chances of a Commons majority after 2015. At the last election, 41 of the 59 Scottish seats were won by Labour. Just one went to the Tories.