A secret report written 30 years ago has been released, stating Scotland's oil revenues could have made a case for repealing the Act of Union.
The North Sea industry was in its infancy in 1974
The advice from economist Gavin McCrone was prepared for ministers and is now available for the public to view.
He said the significance of North Sea oil finds remained in large measure disguised from the public.
But in a covering letter he said he may be giving an SNP government the benefit of too many doubts.
The paper, which is now available for the public to view at the National Archives in Kew, London, was obtained last month by the Scottish National Party under freedom of information legislation.
In the previously confidential advice to ministers, Professor McCrone said that an independent Scotland could be transformed by oil revenues and become a leading power in Europe.
His report, The Economics of Nationalism Re-examined, said that estimates from the SNP that oil could yield £800m by 1980 were far too low.
He conceded that he may be giving an SNP government the benefit of too many doubts but said he wanted to explore whether a credible economic strategy was possible.
Professor McCrone argued that the economy of an independent Scotland, properly managed, would "tend to be in chronic surplus to a quite embarrassing degree".
"Its currency would become the hardest in Europe, with the exception perhaps of the Norwegian kroner," he wrote.
"Just as deposed monarchs and African leaders have in the past used the Swiss franc as a haven of security... the Scottish banks could expect to find themselves inundated with a speculative inflow of foreign funds.
"Thus for the first time since the Act Of Union was passed, it can now be credibly argued that Scotland's economic advantage lies in its repeal."
'Years of betrayal'
Kenny MacAskill, of the Scottish National Party, said the report was proof of 30 years of official lies, cover-ups and betrayal.
In the 30 years since the research, Scotland had suffered low economic growth and manufacturing decline while at the same time oil wealth had "transformed" Canadian provinces and Arabian sheikdoms.
However Scottish Secretary Alistair Darling dismissed the document.
"This is typical of the nationalists, looking back to the past. This document is 30 years old," he said.