Senior academics and university executives have said they believe Scotland's best-known universities would lose access to billions of pounds in funding and joint projects supported by British research councils if the country voted to leave the UK.
It is claimed a number of senior research scientists have already been approached by English universities.
Professor David Weller, director of the Centre for Population Health Sciences at Edinburgh University, said 80 per cent of his centre's work was in collaboration with other UK researchers and cancer charities.
"There's just no way if Scotland was a separate country that kind of arrangement could be sustained," he said. "There are huge concerns in the area I work in."