I Am no lawyer, but new legal advice suggesting Scottish universities could continue to charge fees to students from the rest of the UK (rUK) after independence without falling foul of European discrimination law appears flimsy at best, despite it being welcomed as "game-changing" by the SNP.

Currently, Scottish-domiciled students pay nothing for their tuition at institutions here, but those from rUK pay fees of up to £9000. The charges are possible because, under European Union (EU) law, separate countries within one state, such as the UK, can operate different fee policies, whereas countries that are independent of one another, such as France and Germany, cannot. Conventional thinking thus far has suggested that, in an independent Scotland that remained part of the EU, students from England, Wales and Northern Ireland would become EU students and have to be given parity with those from Scotland. That would mean the end of a new stream of income for universities and would also lead to an increase in competition for places currently being filled by Scots as greater numbers of rUK students crossed the Border in search of a cheap university education.

Admittedly, a neat solution would be to carry on charging rUK students fees after independence and the latest legal advice commissioned by Universities Scotland has been interpreted as offering that possibility. However, the advice rests on just two cases, both of which were unsuccessful for the countries involved. One deals with an attempt by the Belgian government to restrict access to medical degrees by setting quotas for non-Belgian students. The other concerns plans by the Austrian government to introduce tougher entry requirements for non-Austrian applicants by getting them to prove they were suitable for higher education in addition to meeting course entry requirements. In both cases, the courts rejected these approaches, ruling that each country had failed to prove there was sufficient reason for them to be discriminating against students from other countries in such a way.

The chink of light for the SNP is explained by a sentence from one ruling that states: "It could not be excluded from the outset that the prevention of a risk to the existence of a national education system and to its homogeneity may justify a difference in treatment between some students." So the Scottish Government might be able to discriminate by charging fees, but only if it successfully argued the very existence of higher education here was "imperilled" by the influx of rUK students. No easy task.

More worryingly for the Scottish Government is that the advice goes on to say it might "sit more easily" with the EU if Scotland charged all students fees – including Scots – and then offered grants to offset the costs.

Apart from the fact such a solution would itself be open to a legal challenge, it would also explode First Minister Alex Salmond's "rocks will melt with the sun" pledge over introducing fees for Scottish students.