British universities are rapidly expanding the recruitment of overseas postgraduates who pay higher fees, but growth in the number of domestic postgraduates is far slower, a study has found.
The analysis by the Higher Education Policy Institute and the British Library, published on 21 January, urges the Government to make PhDs more attractive to British students to arrest the erosion of the UK's research base.
The number of UK first-year postgraduates grew by 3 per cent between 2002-03 and 2007-08, the report finds.
However, the number of postgraduates from other European Union countries rose by 11 per cent, and the number of non-EU postgraduates - who pay higher fees - increased by 39 per cent.
In 2007-08, the last year for which statistics are available, 44 per cent of doctoral and research masters students hailed from overseas, along with 50 per cent of taught masters students.
The five institutions with the highest number of overseas students as a proportion of their total postgraduates are: the universities of Cambridge (43 per cent), Oxford (37 per cent), Cranfield (36 per cent), St Andrews (34 per cent) and Imperial College London (34 per cent).
Bahram Bekhradnia, director of Hepi, said it had been a period of slow growth for UK postgraduate numbers, and in some fields there had been no growth at all.
"In a way, that has to be a worry. Why are we not getting UK students to take up these courses and potentially become academics?" he said. "On the other hand, you could take the view that we want to recruit the best people from whatever country."
The availability of research grants was likely to be the key factor affecting Britons' take-up of PhDs, he added.
The overall number of postgraduates studying in the UK rose from 249,117 to 8,2 over five years, an increase of 12 per cent.
The study, Postgraduate Education in the United Kingdom, calls on the Government's review of postgraduate provision, led by Adrian Smith, director-general of science and research at the Department for Business, Innovation and Skills, to consider access for UK students. The review is due to report in the spring.
"The future strength of the UK research base will depend in part on doctoral study and a research career becoming more attractive to UK-domiciled students," the Hepi report says.
Fees for overseas students rose by between 37.7 per cent and 46.2 per cent over the five years studied, depending on subject.
But the analysis warns that overseas fees "cannot continue to increase indefinitely: the market share of the US, which is more expensive, diminished last year".
Mr Bekhradnia said: "Partly as a result of the growth in postgraduate students, fees from international students have become essential to the viability of many universities."
Another trend highlighted by the study is the huge growth in taught masters courses.
There were 155,074 students on taught masters programmes in 2007-08 compared with 122,402 five years earlier, a rise of per cent.
Mr Bekhradnia said universities were "creating a market" for these mainly vocational courses, while students were keen to gain skills to help them stand out in the job market.