LEGAL advice which the SNP says is a "gamechanger" on the issue of university tuition fees in the wake of independence has been attacked as flimsy.

The advice was seized upon by Nationalists as the key to solving the problem of how to continue to charge students from the rest of the UK (rUK) up to £9000 a year in the event of a Yes vote.

Under independence, such students would be classed as coming from the EU and would have to be treated in exactly the same as home students, who do not pay fees.

Alex Salmond, the First Minister, told MSPs the legal advice showed that, based on equity and residence, the policy of free education could be pursued in an independent Scotland.

He said: "I know this is inconvenient for the .... parties that want to impose tuition fees on the students of Scotland."

However, opposition politicians highlighted significant flaws in the legal advice, commissioned by Universities Scotland.

Liam McArthur, education spokesman for the Scottish Liberal Democrats, said for the past six years the Scottish Government has failed to find a way of legally charging students from the rest of the EU who attend Scottish universities, despite repeated promises.

"The suggestion there is now a 'get out of jail free' card in relation to rUK students attending Scottish universities in the event of independence lacks credibility," Mr McArthur said.

"It is far more likely that if Scotland votes to leave the UK, rUK students would have the same status as EU students and Scottish universities would be left with a £220 million funding black hole."

Hugh Henry, education spokesman for the Scottish Labour Party, said the advice did not give the unequivocal support for charging fees that had been suggested.

"The Scottish Government need to say what they intend to do and whether it could be justified," Mr Henry added.

Professor David Bell, from Stirling University, said the Scottish Government would not be able to charge students from England the same amount if the country left the UK. "They would have to charge them the same as Scottish students get charged, which is nothing," he said.

However, a spokeswoman for Universities Scotland, which represent principals, said the advice was a basis for looking at how rUK students could be charged in the future, adding: "The legal advice we have received would appear to identify ground upon which it would be possible for the Scottish Government to build a solution."