Scotland is split almost exactly down the middle on independence, according to an opinion poll published as Ruth Davidson claimed the SNP’s leadership is divided over its economic case.
An Ipsos MORI survey for STV news found 50 per cent backing for separation and 50 per cent for the Union among those certain to vote in a second referendum.
If those who were not certain to vote were included, there was 51 per cent support for remaining part of the United Kingdom with 49 per cent opposed.
The survey was published as John Swinney, the Deputy First Minister, continued to insist that North Sea oil was a “bonus” to the Scottish economy despite a senior Nationalist colleague admitting this claim was wrong.
Andrew Wilson, who chairs the SNP’s growth commission, admitted that senior SNP figures including Mr Swinney and Nicola Sturgeon were incorrect when they claimed during the 2014 campaign that oil revenues were a windfall, pointing out they would have been needed to fund public spending.
He said the group, which has been charged with building a credible economic case for independence, would now assume zero oil revenues. However, this leaves Scotland with a higher onshore deficit than even Greece.
The “bonus” claim was further undermined by official figures published this week showing the North Sea making a £200 million loss for the taxpayer in the 2015/16 tax year and a profit of only £100 million in the current year.
Ms Davidson’s claim of division in the upper echelons of the SNP came Nicola Sturgeon told the BBC that she considers autumn next year to be the “common sense time” for a second referendum.
Mr Swinney, who took First Minister's Questions while she attended a memorial event for those who served in the Afghanistan and Iraq wars, said oil was considered a "bonus" to the economy and had "propped up" the UK economy for many years.
He said: “I certainly consider oil to be a big bonus. It has certainly been a huge bonus for the United Kingdom—there has been £300 billion-worth of revenues for the United Kingdom.
“Of course, I am not the only person who thought that oil was a bonus. In 2014, the Prime Minister came to Aberdeen and said that, if Scots voted no in the referendum, there would be a £200 billion oil boom bonus for Scotland.”
But Ms Davidson said the SNP's campaign had been "taken apart" by one of its own side, while Kezia Dugdale, the Scottish Labour leader, said the economic case for independence is "well and truly bust".
Speaking after their exchanges, the Scottish Tory leader said: “We now have a very stark contradiction at the heart of the SNP. Its chief financial adviser says oil was the basis on which a separate Scotland would have been built.
“But the Deputy First Minister says it was merely planned as a bonus. They can’t both be right, and this contradiction exposes that the entire economic prospectus on which the SNP based its case for independence was bogus.”
Ms Dugdale said there was a £21 billion difference between the oil taxes the Nationalists said would be generated in the first two years of a separate Scotland – 2016/17 and 2017/18 - and new figures published by the Office for Budget Responsibility to accompany Wednesday’s Budget.
The Ipsos MORI survey also found that 52 per cent believed Ms Sturgeon is doing a "good job representing Scotland's interests in the process of the UK leaving the EU". Only 24 per cent said the same of Theresa May.
Mark Diffley, the pollster’s Scotland director, said: “This poll suggests some modest movement back towards independence since we last measured opinion six months ago.”