Scotland's universities have a proud record of scientific and academic achievement which is internationally recognised.

To maintain that, the sector needs to be well-funded, with individual institutions able to access the resources they need to compete.

So it is understandable higher education leaders are alarmed about changes by the UK Government that could make this more difficult.

Already battling to reverse a trend which has seen fewer students from England, Wales and Northern Ireland applying to take up courses north of the Border, Scottish universities fear that job will be made harder due to Chancellor George Osborne's ongoing marketisation of the rest of the UK's (rUK) higher education system.

With caps on student numbers lifted for English universities, the numbers looking to come and learn in Scotland may well decline.

Figures currently show an increase in students from the rUK but this is misleading as Edinburgh University accounts for nearly all of the rise -most universities have seen a decline.

So the new fears about university income are hardly irrational.

Around 4800 rUK students opted to study in Scotland last year, and provided a significant chunk of the sector's income.

But allowing English universities to recruit an extra 30,000 students in 2015, and more thereafter, is bound to have an impact on numbers.

The sector here will have lost £92m a year in public funding by the end of 2015/6 due to the gradual withdrawal of cash in the expectation that fee income replaces this. If that is not forthcoming it will be highly challenging for the sector. Scottish universities charge fees of up to £9000 a year only to rUK students. If they cannot recruit them, they could be left badly short of cash.

NUS Scotland, which opposes any fees, is urging universities to reconsider fee levels or offer more financial support. Neither measure seems likely to address this fresh cash headache for the sector.

It is hard not to sympathise with university leaders as they struggle to plan ahead in the face of multiple threats. This is an added uncertainty they do not need.

The Education Committee, with whom the problem is to be raised today, is already looking at the potential impact of an independence Yes vote on university funding.

It seems likely a future Scottish Government would need to revisit the legality of charging rUK students, when other EU students are not charged fees.

The Scottish Government insists the status quo will continue in the event of independence and says there is a long history of rUK students wanting to come to study in Scotland, so the sector can rely on fee income.

The former may have to be tested in the courts or through protracted negotiation. The latter is in question because of Westminster policy changes.

Universities are demanding Scottish ministers provide greater clarity ahead of September's vote. It is increasingly pressing that they get it.