British universities are at risk of “collapse” after Brexit as the future of tens of thousands of foreign academics is called into doubt, according to a new report.

Changes to immigration rules will make it increasingly difficult for universities to hire and retain top academic talent, which could put their high standing in international league tables at risk, according to the British Academy.

Currently 40,000 non-UK EU staff work in UK universities, with modern languages, mathematics, physics and economics predicted to be particularly badly affected by Brexit because of their high concentration of EU staff.

“You take all those staff members away and the universities will just collapse,” says Professor Ash Amin, foreign secretary of the British Academy.

The high proportion of international staff at UK universities is a testament to the ability of UK institutions to attract talent from overseas, the report says. This is especially true for the humanities, which the British Academy focuses on, and which made up six of the top 10 subjects in the report’s ranking of EU staff proportions.

The figures are particularly troubling in some regions. Nearly a quarter of all academic staff at higher education institutions in Northern Ireland, for example, are from non-UK EU countries.

As it stands, there is a great deal of uncertainty surrounding the future status of EU nationals in the UK, especially those who have not already accrued five years of residency. The authors of the report warn that this needs to be addressed in order to retain EU researchers in UK institutions.

“It is critical that the Government takes action and puts an end to this uncertainty,” said Professor Amin. “Today’s report depicts precisely what is at stake: the UK’s position as a world leader in higher education and research.”

These fears are not unfounded, with over 1,300 academics from EU countries already reported to have left UK universities in the past year. “We are hearing reports, especially from early career academics, who are feeling quite uncertain when making the decision about whether to build a career here,” Prof Amin added.

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“The Government needs to make a decision very soon about the right of Europeans to stay in the UK,” he said. “We are calling on Government to guarantee a right to remain indefinitely for non-UK EU academics and their dependents working here.”

A Government spokesperson told The Independent: “We are within touching distance of a deal on citizens’ rights and have made guaranteeing the rights of EU citizens a priority.

“The Government is committed to the UK’s world-class higher education sector and we will ensure that universities can continue to attract international students and staff after we leave the EU.