The status of UK higher education as one of the world's top recruiters of international research students is under threat and must be protected against increasing competition.
That is the conclusion of a study published this week, which warns that the sector must act now to protect its competitive edge.
The report by the Higher Education International Unit found that the UK and US were the two most attractive destinations for postgraduate research students, followed by Germany, France and Australia.
The UK has about a 15 per cent share of the international market, giving it the highest number of international postgraduates per capita anywhere in the world.
The country plays host to more than 50,000 research students from overseas, and postgraduate numbers have grown at an annual rate of more than 4 per cent in recent years.
Nationals from countries such as China, the US, Greece and India account for 42 per cent of all postgraduate researchers in the UK, compared with 33 per cent in the US.
Rick Trainor, president of Universities UK, said: "The benefits are clear to see: not only do these students directly raise the research output of our universities, they augment the knowledge base of the country, heighten the UK's capacity for innovation and enhance its strategic position in the future international economy."
Because other countries want to enjoy the benefits researchers bring, there is fierce competition from the likes of the US, Germany, India and Pakistan to attract postgraduates.
Professor Trainor said it would be unwise for UK higher education to rest on its laurels.
Among areas of concern identified in the report is a dip in recruitment from China last year and falling demand for courses including mathematics, engineering and technology.
The study found that the UK's success was due largely to the achievements of institutions in a small number of countries.
Ten countries and 18 universities account for half of all recruitment, and there is a dangerous overreliance on US students in humanities and the arts and Chinese students in engineering and technology, the International Unit says.
The report says the major factor influencing researchers' choice of destination is the reputation in research and teaching, in which the UK performs well against its competitors.
However, funding support is also vital, the study found. Scholarships and affordable fees are a major draw, and costs - both living expenses and fees - are a deterrent.
This factor has particular resonance in the UK. It is seen as one of the most expensive destinations, and two thirds of international postgraduate research students meet their costs from sources outside the country.
With the number of self-funding students falling, in particular from Japan and other East Asian countries, the report says UK universities must invest more in financial support for postgraduates.
The study says it is inevitable that the UK will lose some market share, but the right strategy could ensure that overall numbers rise, it adds.
Among the recommendations is the development of a national strategy to market the "UK doctoral brand" overseas. This should aim to expand the range of countries from which PhD students are recruited, and it should be partnered with a review of funding and scholarship provision.
The report also says universities should invest more in their websites (which are a major source of information), develop their own recruitment strategies with a focus on undergraduate students (who often stay on as postgraduates) and send their "big-name" staff overseas to build up the university's reputation.