The warning follows the introduction of the most expensive degrees in the UK by the universities of St Andrews and Edinburgh.

From next year, both institutions will charge £36,000 to students from the rest of the UK (RUK) for a four-year degree. And under new rules, the number of RUK students that universities can recruit will no longer be restricted.

Professor John Holmwood, an academic from Nottingham University, believes higher fees and the lifting of the cap on numbers will lead to a sharp rise in the number of students from privileged backgrounds coming to Scotland. Speaking in advance of a lecture today at Edinburgh University on the impact of fees, he said: “The problem is that students from better off backgrounds, such as those from private schools who are used to paying fees, will tend not to be put off by having to pay more.

“By contrast, students from poorer backgrounds are much more likely to view going to university as incurring debt, rather than making an investment in their future. ”

Mr Holmwood, who campaigns for universities to dedicate themselves to the public good, also said the way the Westminster Government had drawn up its fees policy undermined the Union between Scotland and England.

“Government policies and electoral politics have created a new divergence in higher education,” he said. “Ill-thought-out and opportunistic policies to tackle fiscal deficit may have profound consequences for the Union itself. It enables the creation of the argument we are different countries with different values about higher education when, in fact, the public in both countries share concerns about higher fees.”

The need to alter the fee level paid by RUK students in Scotland was prompted by UK Government changes to university funding.

Because institutions were allowed to charge up to £9000 a year in the rest of the UK, the SNP Government decided to let Scots institutions charge similar fees to prevent them becoming a cheap option.

A Scottish Government consultation on fees anticipated RUK students would not have to pay more towards tuition fees in Scotland than in their own country.

However, St Andrews and Edinburgh chose to set fees at a higher level than competitor universities in England.

Alastair Sim, director of Universities Scotland, which represents university principals, said: “Scotland’s universities are putting in place a range of generous bursary schemes to ensure students from diverse backgrounds across the UK are able to take the opportunity to study here.”

However, Robin Parker, president of NUS Scotland, hit back: “We know tuition fees put off the poorest students, but degrees that will be the most expensive in the whole of the UK will surely make these institutions the preserve of the elite.”