The right of universities in Scotland to levy different fees for students from the other home nations has been defended by the Scottish Executive amid reports that the European Parliament is investigating claims of "discrimination".
The executive said its approach to fees complied with European Union guidelines that outlawed discrimination between countries but not between regions within a member state.
Nevertheless, the European Parliament's petitions committee has asked for legal advice about the Scottish approach after receiving complaints from two English students.
At present, undergraduates from England, Wales and Northern Ireland who study in Scotland pay £3,600 in fees.
Students from Scotland and EU states pay no fees in advance but are charged £2,000 after graduation.
The 11,000 Scots who study south of the border pay the same £1,250 tuition fee as their English counterparts.
A Scottish Executive spokesman said the fee system was in line with EU guidelines and that the question of discrimination had been considered and ruled out by European Commissioners in 2001.
"The anti-discrimination rules apply to EU member states and not the home nations of the UK, so the rules do not forbid a range of charges within the regions of a nation," the spokesman said.