The ICM survey showed a 3 per cent increase in backing for independence if voters in Scotland thought the UK was “very likely” to pull out of the EU, with David Cameron pledging an in-out referendum on Europe if he is elected as Prime Minister in the 2015 General Election.
Support for the No campaign also slumped when voters were asked which side they would support, if they thought in September that British withdrawal from the EU was a real prospect in a “few years’ time”.
Backing for independence stood at 37 per cent, while No was on 43 per cent and the undecided on 20 per cent if Scots thought the UK as a whole would vote to come out of the EU in the in-out referendum Mr Cameron has promised, the survey of more than 1,000 adults showed.
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The same poll for The Scotsman’s sister paper Scotland on Sunday showed voters divided differently on the question of independence when they were asked: “Should Scotland be an independent country?”
Independence was backed by 34 per cent, with 45 per cent wanting to remain in the UK and 21 per cent undecided in the original poll question on referendum voting intentions.
However, when the “don’t knows” were excluded from today’s results, the numbers of those who said that the threat of an EU exit would make them support independence surged to 46 per cent, with 54 per cent intending to vote No.
In a separate finding, 70 per cent of those polled said they expected the No campaign to win the referendum, with only 30 per cent expecting a vote in favour of independence on 18 September.
The ICM’s findings suggest the issue of Europe could influence the outcome of the referendum, with the poll showing overwhelming opposition in Scotland to EU withdrawal.
Nearly half – or 47 per cent – of the 1,002 adults interviewed said they would vote for the UK to “stay in” the EU, with just 33 per cent saying they would support British withdrawal. The remainder of those polled were undecided on which way to vote in the EU referendum Mr Cameron has promised.
Opposition to EU withdrawal remained at a high level north of the Border, despite the rise of the anti-EU party Ukip, which gained its first Scottish MEP in May’s European elections and made sweeping gains in the rest of the UK.
Support for EU withdrawal in the UK as a whole has consistently stood at about 40 per cent, with some polls south of the Border showing a lead for the eurosceptic side.
The Scottish Government last night claimed the poll showed many voters feared that a No vote would put Scotland on the “fast-track out of Europe”.
A spokesman for First Minister Alex Salmond said: “David Cameron’s ham-fisted diplomacy has pushed the UK closer to the exit door of Europe, against Scotland’s wishes.
“Westminster is dancing to a Ukip tune, and this poll shows people are clearly worried that that has put us on the fast-track out of Europe, with all the damaging consequences it would have for jobs and investment.”
“Only a Yes vote in September will avoid that possibility and secure Scotland’s place in Europe.”
A spokesman for Yes Scotland said: “As this poll shows, a growing number of Scots are coming to realise the best way to safeguard Scotland’s continued membership of the European Union is to vote Yes in September.”
However, No campaigners claimed the 3 per cent boost in support with the threat of EU withdrawal would still lead to a heavy defeat for independence.
Scottish Labour’s Europe spokeswoman Patricia Ferguson said: “This shows that the Yes campaign’s scaremongering on EU membership has had almost no impact on the people of Scotland who see through their desperate attempts to cover up the holes in the case.
“What the people of Scotland really want to know is the price of an independent Scotland’s membership of the EU and so far Alex Salmond and Nicola Sturgeon haven’t been able to provide any answers.”
Tory MSP Alex Johnstone claimed that “dissatisfaction with the EU is equal or greater” in Scotland than that in other parts of the UK.
Mr Johnstone said: “I don’t think there is any real difference in opinion on the EU between Scottish and English voters.
“But any difference that might be hinted at here is largely due to the Yes campaign setting out a false prospectus on Scotland’s future in Europe.”
Scotland Ukip MEP David Coburn said there was opposition to the EU among SNP supporters as well as No voters.
He said: “My door-to-door experience is that the vast majority of people do not like the EU and there’s not much difference between folk in Scotland and England on this. There are quite a few Scottish Nationalists who don’t want to be part of the EU.”
A spokesman from the anti-independence Better Together campaign said: “It is clear that no matter how the question is asked the majority of Scots favour Scotland remaining part of the UK and are saying no thanks to separation.”
John Curtice: ‘Wisdom of the crowd’ may have the answer
SCOTLAND will not be surprised if the result is close on 18 September. But most people will be startled if the decision goes in favour of Yes.
In our latest poll, ICM asked people to say what they thought the result of the referendum would be, by stating what percentage of the vote they think the Yes side will win.
The poll puts Yes on 43 per cent of the vote. However, on average those who took part in the poll expect Yes to win 47 per cent. That suggests that many voters believe there is still plenty to fight over – and that they do not think the result is such a foregone conclusion that they need not bother to cast a vote.
However, no less than 70 per cent reckon the No side will emerge victorious. Only 30 per cent believe Scotland will vote to become independent. These proportions are the same as they were when ICM last asked the question in March.
But there is one section of the nation that will not be surprised if the Yes side wins – Yes supporters. Two-thirds of them believe a majority of Scots will vote for independence.
Such optimism might help explain why polls and social media surveys show that Yes supporters continue to be more actively involved in the campaign. They have not lost hope of victory.
Nevertheless, Yes voters are markedly less confident of success than their counterparts on the No side. No less than 94 per cent of No supporters expect their side to win. Indeed three-fifths expect to win quite comfortably, securing more than 60 per cent of the vote.
There will be a lot of very disappointed No supporters should Scotland decide it does wish to leave the UK.
In contrast, most undecided voters (58 per cent) think the result will be relatively close, with neither side winning more than 60 per cent – though most (76 per cent) still expect No to win.
It has been argued that sometimes the “wisdom of the crowd” can provide a better guide than the polls. And given that one of the features of this referendum is that the polls do not agree on how far No are ahead, who can be sure that this time it will not be the crowd that gets the forecast right?
• John Curtice is professor of politics, Strathclyde University