The different countries of the UK have very different ideas about a lot of things, and university fees are no exception.

With the introduction of £9000 tuition fees in England, both Scotland and Wales moved promptly to protect their own nationals but, in a UK divided on how to charge for a degree, who looks after making university accessible to poorer or disadvantaged students from any of the regions?

First Minister Alex Salmond has declared that "the rocks will melt with the sun" before his Government would charge fees from Scottish students. Free tuition is justified as a citizenship right and a condition of wider access to university for disadvantaged students. In Wales, the Government followed England in charging up to £9000 fees but added its own twist. Welsh students, and other EU citizens studying in Wales, get a government grant, potentially more than £5000 a year, to make up the difference between the fees paid and the fees they would have paid before the 2012 increase.

Students from England, Wales and Scotland face the £9000 maximum annual fee if they study in Northern Ireland but Northern Irish students still only pay fees of around £3500 if they study in the region. But, like their Scottish counterparts, they are on their own if they want to study elsewhere. Whereas only about one Scottish student in 20 studies outside Scotland, around one-third of students from Northern Ireland study elsewhere in the UK. Many have no option but to leave because they lack the qualifications to win a place in Northern Ireland. Having to pay higher fees only makes their position worse.

As the UK nations plough their own paths on fees, they move further away from the bigger picture. Governments and universities are increasingly thinking about how students from under-represented backgrounds can get a fairer shot at a good education, particularly when that education comes with the daunting prospect of significant debt. But when the different governments of the UK think about tackling this, should they continue to look after their own, as they do when setting fee policies?

All three devolved administrations - most conspicuously Scotland - discriminate in financial terms in favour of their own students and treat disadvantaged students from other parts of the UK very differently to disadvantaged students from within their own borders. Higher education, by implication, is a right for Scottish citizens but not for citizens from other parts of the UK.

In the past, students from the rest of the UK studying in Scotland - more than one in eight of all UK-domiciled students at Scottish universities - have been disproportionately well qualified and middle class, often from independent school backgrounds. Will the students who cross borders to study in Scotland under the new fees regime be an even more socially selected group?

Whose responsibility is it to make sure that this does not happen, the Scottish or the UK Government's? Conversely, the relatively disadvan­taged students from Northern Ireland who have to study elsewhere because they cannot get into the courses they would like to enter at home will be doubly disadvantaged, because they may have to pay fees at more than twice the level. Whose responsibility are they: that of the Northern Ireland administration or of the UK Government?

On the other hand, should the UK Government take responsibility for the situation that has created these dilemmas? The idea for £9000 fees did, after all, come out of Whitehall in the first place. There was no appetite for an increase in fees in any of the devolved administrations; indeed, the Welsh Government did not want to raise fees the last time round, in 2006, but it had to do so (one year later than England, in 2007) because of the close interdependence with England. The UK Government took the decision to increase fees in order to address problems in England but this decision, and the knock-on effects on the block grant paid to the devolved administrations, have created new problems for the other countries of the UK.