Negotiations that would follow a vote for independence could result in conflict between Scotland and the rest of the UK, according to the leader of the pro-Union campaign.
Former chancellor Alistair Darling, chair of the Better Together group, claimed that the negotiations could be “totally destructive”.
He made the comments as the Scottish Government prepares to publish its white paper on independence on Tuesday.
Deputy First Minister Nicola Sturgeon said the document will be the “most comprehensive, detailed blueprint for independence of any country”.
The white paper is expected to make the case for an independent Scotland to keep the pound by creating a currency union with the rest of the UK, a position that has been set out by the Scottish Government. Mr Darling said such a currency union is a “legal straitjacket” and that it is by no means certain that the rest of the UK would sign up to it.
Speaking at an event organised by the Institute of Chartered Accountants of Scotland in Edinburgh, Mr Darling said that Scottish Finance Secretary John Swinney has “said there was going to be a currency union, that was what was in the white paper, if people voted in favour of independence that’s what the rest of the country would agree to, and it would be very difficult if they didn’t”.
The Labour MP said: “That seems to me to be getting into very dangerous water, setting up a conflict between Scotland and England, which some Nationalists thrive on I’m afraid and I don’t like.
“In a negotiation, both sides have to agree to something. You can’t assume the other side are going to say ‘OK you can have it, no questions’.”
On such issues, “quite legitimately, the rest of the UK would have a view”, Mr Darling said.
“If we vote in favour of independence next September, that result will be accepted by everyone. Whether you like it or not, that is what democracy is about.
“But no one has ever agreed in advance: if we vote for independence, here are all the things that have been agreed. There then has to be a detailed negotiation and discussion about 101 different things.
“And that’s why there’s so much uncertainty here about currency, pensions, regulation, debt, or building warships on the Clyde. All these things are up for grabs.”
It is “totally unreasonable just to assume” both parties would reach “agreement on every single point, without any question” in the discussions, he added.
“The last thing we want in this country, Scotland and the rest of the UK, is to end up with Scotland against England. It would be totally destructive and I don’t want to see it,” he said.
Ms Sturgeon said all the proposals in the white paper would be “reasonable and sensible and rational, and in the interest of both the UK and Scotland”.
She said: “If, following a Yes vote, we are negotiating in the spirit of the Edinburgh Agreement, then these things will be matters that are sensibly negotiated because the provision in the Edinburgh Agreement about both sides respecting the result (of the referendum) and working constructively in the best interests of the people of Scotland and the rest of the UK is something we both signed up to.”
If there is a Yes vote the “dynamic changes completely” between the Scottish and UK governments, she said.
In that situation, “the people have spoken, the democratic decision has been taken and we then sit down and negotiate sensibly”.
If Scotland votes to leave the UK, the people would have endorsed the white paper, “that prospectus, as the starting point of an independent Scotland”.
Mr Darling said: “We’ve all signed up to abiding by the outcome of the referendum. But whatever happens after that, there would have to be a negotiation.
“And it is abundantly clear to me there is increasing resistance on the other side of the border to entering into a currency union, because of the democratic implications.”
He said: “That inevitably takes you to increasing political union which, ironically, is the very thing the Nationalists want to end.”
By seeking a currency union with the rest of the UK, the Scottish Government “would be asking the rest of the UK to enter into an agreement in a currency union whereby, in theory, a foreign country (Scotland) could veto any tax or spending or borrowing policy,” he added.
Ms Sturgeon, also speaking at the event, insisted that a currency union would still give an independent Scotland control over taxes and that was the best option for both Scotland and the rest of the UK.