Voters will have to wait a year to find out why the SNP believes an independent Scotland would remain part of the EU, the First Minister has told MSPs.
Alex Salmond said that the Government will set out its stall on Europe in its white paper on independence, due to be published in a year.
His statement came as opposition parties claimed comments by the President of the European Commission indicated Scotland would have to apply for EU membership if it gained independence from the rest of the UK.
Jose Manuel Barroso told a BBC reporter he would not speculate about possible "secessions" within existing states, such as the UK.
However, he added: "A new state, if it wants to join the EU, has to apply to become a member of the EU, like any state."
At First Minister's Questions on Thursday, Mr Salmond again insisted Scotland would still be part of the EU if it were to become independent.
"Scotland is part and will remain part of the European Union as an independent country," he said.
But Scottish Labour leader Johann Lamont challenged him on the issue, saying Mr Barroso's comments made it clear that "the new state of Scotland would first have to apply to be a member of the European Union and, if successful, adopt the euro as our currency."
The First Minister responded: "Scotland is not an accession state; we've been members of the European Union for 40 years.
"We are not in the position of a country which is not part of the European Union, and that means of course there have to be negotiations, but the crucial point is that these negotiations take place from within the context of the European Union."
Ms Lamont hit back by saying if Scotland would not be a new state "you wonder what they (the SNP) have been arguing for the last 100 years".
With the Scottish Government appealing an official ruling compelling them to reveal whether they have taken legal advice on the issue of Scotland's future in the EU, Ms Lamont told the SNP leader: "Instead of telling the people of Scotland what advice he has had, he is using our money to fund a court action to stop us knowing what the First Minister knows.
"If the First Minister has advice which does contradict what President Barroso has said, why does he not remove all doubt and publish it?" she asked.
"Dialogue between the people and their representatives is essential in a genuine democracy."
Mr Salmond argued he would be breaching the ministerial code by disclosing legal advice on the issue.
However, he added: "I do believe I have a solution for Johann Lamont which reconciles my obligation within the ministerial code and, I believe, the democratic imperative of information for the people of Scotland.
"We have set out our intention to publish the white paper on independence this time next year.
"I give her my guarantee that that white paper, which sets out the full context of the independence proposition, will contain a detailed assessment on the particular question of membership continuing of the European Union.
"That seems to me a pretty reasonable proposition and folk in Scotland will be looking forward to reading that white paper, the passport to independence and freedom."
A spokesman for First Minister Alex Salmond later suggested that the United Kingdom is a "voluntary union" between two previously "recognised states".
He said: "Scotland was a recognised state until it entered into 'voluntary union' with the rest of the UK to form a new state (in 1707).
"A House of Commons briefing paper on international law says, in such cases of a voluntary union of two recognised states, it 'gives rise to a presumption in favour of continuity of treaties with regard to each component'."
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