Media playback is unsupported on your device Media caption Fiona Hyslop says ministers will not reveal the legal advice on the EU

The SNP government has received legal advice on an independent Scotland's membership of the EU, but it has refused to reveal what it says.

External Affairs Minister Fiona Hyslop confirmed to BBC Newsnight Scotland that advice had now been seen.

But she added that no government, whether at Holyrood or Westminster, would reveal such advice.

In October last year, Deputy First Minister Nicola Sturgeon said she had asked for legal guidance on the EU.

That advice was commissioned from the Lord Advocate Frank Mulholland and it is understood he has now handed that over to the Holyrood administration.

Ms Hyslop told BBC presenter Gordon Brewer: "We have received legal advice. No government, whether it is the UK government or the Scottish government, would disclose that.

Analysis "John Bruton should know a thing or two about how the European Union works. "After his spell as Ireland's prime minister 1994-1997, he served for five years as the EU's ambassador to the United States. "In his judgement, an independent Scotland 'probably could' secure membership of the EU in the 18 months between a "yes" vote in Sept 2014 and the SNP's target date for independence in March 2016. "His view has been welcomed by the first minister as a 'sensible' contribution to the debate. "However, Mr Bruton believes Scottish membership would require a new treaty of accession ratified by all 28 member states. "The Scottish government has acknowledged the need to reach agreement with other EU countries. "But it is understood ministers think a simpler treaty amendment would be sufficient. "This is presumably a view informed by the legal advice the government has now received from Scottish law officers. "In any event, the government has moved a long way from arguing that Scottish membership of the EU would be 'automatic' upon independence. "Similarly, their opponents have generally moved away from arguing that an independent Scotland might be excluded from the EU to question the quality of the deal that a Scottish government would be able to negotiate." Watch my interview with John Bruton

"But what we have said, and Nicola Sturgeon said this in October, is the White Paper would set out the proposals."

Labour MSP Ken Mackintosh, who was also being interviewed by Newsnight Scotland, asked Ms Hyslop: "Given that we are going to have a referendum next year, why won't you at least publish the terms of the legal advice before that referendum?

"Surely, it is pretty central to the arguments you are putting, surely the Scottish people will have the right to see that legal opinion before we vote on it?"

Ms Hyslop told Mr Macintosh that the material was "confidential".

She added: "The important thing is the White Paper that will set out the terms for the independence proposal will be consistent with the legal advice that we have received. Now, that is the reassurance that you are looking for, that was the reassurance promised by Nicola Sturgeon in October."

Ms Hyslop made her comments during an interview to discuss the view of former Irish prime minister John Bruton who believes Scotland "probably could" achieve EU membership within 18 months of a yes to independence.

The Scottish government wants to negotiate "continuing" EU membership if there was a yes vote in 2014.

However, Mr Bruton told the BBC he thought a formal treaty of accession would still be required.

He added: "There will always be uncertainty about what might happen afterwards, you are never going to get 100% assurance on all of the points you want assurance on."

Mr Bruton, who served as Taoiseach of Ireland from 1994 to 1997, went on: "The EU, ultimately, while it is based on rules and law, is a practical, political enterprise which works on the basis of mutual interest and compromise.

"Compromises are always found, sometimes with a bit of suspense involved, but they are always found to the big difficult issues in the EU."