A leading human rights lawyer is planning a legal challenge to Scotland's university funding system.
Phil Shiner said the policy breaches the European Convention on Human Rights by charging students from other parts of the UK to study north of the border.
Scottish students studying at home do not pay tuition fees while some 22,000 English students in Scotland do.
The Scottish government has defended its policy and says it is acting within the law.
Mr Shiner, of Public Interest Lawyers, is already representing two students who have been given a full judicial review to challenge the increase in tuition fees at England's universities.
The legal team acting for Callum Hurley, from Peterborough, and Katy Moore, from London, are expected to argue that poorer students and those from ethnic minorities could be discriminated against by the change.
Mr Shiner has now turned his attention to the fees structure in Scotland where English students pay between £1,820 and £2,895 per year, which will increase to up to £9,000 from next year.
He believes that ministers in Scotland have "misinterpreted the law".
Mr Shiner said the Scottish fees system contravened the European Convention on Human Rights and could also be in breach of Britain's Equality Act.
But a spokeswoman for the Scottish government said: "We are clear that the proposals set out are lawful.
"Tuition fee arrangements are based on "ordinary domicile" not nationality."
She added: "In an ideal world, no students would pay fees. Our main priority has to be to protect opportunities for Scottish students to study at Scottish institutions by maintaining free education north of the border.
"With the UK government introducing tuition fees south of the border of up to £9,000 per annum, Scottish students studying in England will continue to receive financial support in the form of bursaries and loans."
From September 2012, universities in England will be allowed to raise tuition fees to up to £9,000 per year.
The UK government originally said that figure should only be set in "exceptional circumstances", but so far two thirds of universities have indicated that they want to charge that amount for all or some of their courses.
Tuition fees will be covered by student loans, which graduates will begin paying off once they earn at least £21,000 a year.
Under EU rules, students coming to Scotland from other European countries have to be treated in the same way as Scottish students.
But Scotland's Education Secretary Mike Russell is seeking an end the rule which could be seen as a cheap option for Europeans who would have to pay for education at home.
Currently, nearly 16,000 EU students attend Scottish education establishments, costing the taxpayer £75m a year.
At the beginning of this year Mr Russell said the funding loophole was "no longer tenable".
Students in Northern Ireland who decide to go to another part of the UK which charges higher fees will have to pay them.
However, the government is expected to make a higher student loan available to students who decide to take on the more expensive courses outside Northern Ireland.
In Wales, the Welsh government said fees would rise to up to £9,000, as in England, but the government would meet the extra cost to Welsh students studying at any UK university.