The prospect of an independent Scotland staying in the European Union has been described as "a corpse" after the UK Government categorically ruled out the SNP's proposal to avoid the normal accession process.

The Scottish Government's plan is now "riddled with bullets", Scottish Secretary Alistair Carmichael said following an appearance at Holyrood's Europe and External Relations Committee.

Scotland would still be a member of the UK and EU between the referendum and independence day, and it will be up to the UK Government to negotiate Scotland's future relationship with the EU in that time.

The SNP-administration hopes to circumvent the normal EU accession process, set out in article 49 of the Lisbon Treaty, by asking Westminster to propose an amendment to the treaty to write Scotland in as a continuing state, using a procedure set out in article 48.

Chancellor George Osborne has already categorically ruled out sharing the pound in a currency union with an independent Scotland.

When asked to follow suit and categorically rule out using article 48, Mr Carmichael said: "That has been done.

"The UK Government is perfectly clear that the purpose of article 48 is for treaty revisions. The purpose of article 49 is for accession applications.

"The difficulty for the Scottish Government is you require to get agreement ultimately on all 28 member states, so getting a categoric position from the UK Government is only one 28th of what they need to do."

When pressed again to be as categorical as Mr Osborne, Mr Carmichael said: "It is the view of the UK Government that article 49 is the procedure. That is not going to change."

Conservative MSP Jamie McGrigor had called on Mr Carmichael to "shoot the fox" of article 48.

Speaking after the committee, Mr Carmichael said: "I think that is a fox, the corpse of which is riddled with bullets. It is barely recognisable as a fox any more."

Mr Carmichael said Scotland will be treated "as a guinea pig" by the rest of the EU.

"The Scottish Government is taking us down an untested constitutional path with no idea where it will lead," he told the committee.

"My concern is that Scotland is going to be treated as a guinea pig, with no idea about what the experiment will do to us."

Supporters of independence say the Conservative promise of an in/out referendum on the EU in 2017 poses a greater threat to Scots' EU citizenship.

But Mr Carmichael, a Liberal Democrat MP, said he expects this referendum to be a "red line" for his party if they remain in coalition after the 2015 general election.

"It has been a red-line hitherto and I would expect that to continue in the future," he said.

"Perhaps we are establishing a course of conversation here - once you look into the future and try and guess what is going to happen very little is ever certain."

Mr Carmichael also rejected the opinion of European Court judge Sir David Edward, who said Scottish citizens would not automatically lose their EU citizenship if they voted to leave the UK.

He cited the case of suspected fraudster Janko Rottman, who lost his German and Austrian dual citizenship and was rendered stateless by the EU.

Mr Carmichael said: "The court heard that a member state must exercise its powers to withdraw an individual's nationality compatibly with the principles of EU law.

"That in itself is a very clear recognition by the European Court of Justice that the question of citizenship in EU terms of the sort that Sir David was talking about is quite different and that it can indeed be withdrawn.

"And I think it would be quite consistent with that judgement to say that if Scotland were to vote to leave the UK and tends to leave the EU then one of the consequences of that would be a loss of EU citizenship.

"That would certainly not be contrary to any principles of EU law."

The judgement in Rottman V Bavaria concluded: "It is not contrary to European Union law for a member state to withdraw from a citizen of the union the nationality of that state acquired by naturalisation when that nationality was obtained by deception, on condition that the decision to withdraw observes the principle of proportionality."

Committee convener Christina McKelvie expressed doubt that the UK Government would veto the use of article 48 if Scotland becomes independent, suggesting it was the most "pragmatic" solution for both states.

She also cast doubt on Mr Carmichael's resolve to act in the best interests of Scotland.

"I am absolutely confused today, because I'm not sure whether the Secretary of State for Scotland is Scotland's man in Westminster or you are Westminster's man in Scotland.

"It seems to have shifted back and forward all morning."