Universities are becoming increasingly dependent on overseas academic talent, a survey by The Times Higher has revealed, prompting fears of a dwindling supply of home-grown PhDs considering academic careers.
The 16 universities surveyed reported that on average 35 per cent of the academic appointments they had made in the past two years had been awarded to applicants from abroad.
This suggests a significant increase on the number of overseas appointments made in previous years - reported as 29 per cent in the sector as a whole for 2003-04.
At major research institutions, just under half of appointments go to applicants from outside the UK. Oxford University reported that 48 per cent of academic positions in the past two years were filled by overseas candidates, while at Imperial College London the figure was 46 per cent.
The tendency to look to other countries for researchers was strongest when filling junior fixed-term positions. Just over 40 per cent of postdoctoral research assistants came from outside the UK, the survey found.
The results have renewed concern that universities are turning to better qualified overseas researchers who, unlike their British counterparts, are willing to work for low salaries.
Jonathan Whitehead, head of parliamentary and public affairs at the Association of University Teachers, said: "It seems that (British) people just aren't going for jobs in this country. That's why universities go overseas."
Paul Mackney, general secretary of lecturers' union Natfhe, said: "The recent increase in this flow from abroad may be due to the worsening conditions and career prospects of UK academics compared with other professionals, which has made an academic career less attractive."
Louise Ackers, professor of European law at Leeds University and a researcher on the migration of academics, said there was "a declining supply of home-grown staff. There is a level of internal brain drain in the UK, as large numbers of young researchers are lost to other sectors, reflecting pay and better conditions."
She added: "I think this is a serious issue to confront - others think it doesn't matter so long as we can recruit from abroad."
Tony Gardiner, from Birmingham University's School of Mathematics, said:
"We've set up a number of rival policies that effectively force universities into appointing the best research quality they can find.
"The research assessment exercise is looming and people can't think of anything else. British students are left to go out into the job market rather than academia," he said.
There are also concerns that the increased flow of researchers into Britain could affect the health of academia in other countries.
Mr Mackney said: "There is a danger that young academics from abroad may be offered exploitative terms: poorly rewarded posts on temporary contracts, with few career opportunities."
Natfhe and the AUT will host a conference next March on issues relating to the migration of academic labour.
The following universities took part in the survey: Oxford, Warwick, East Anglia, Glamorgan, Glasgow Caledonian, Reading, Edinburgh, St Andrews, Birmingham, Essex, Bristol, Manchester, Imperial College, Central England, Newcastle and Cardiff.