Lesser-known universities are being accused of using overseas students to "prop up" their finances, with new information showing only one in 20 foreign students went to a top 10 university.
Cardiff Metropolitan University, a non-Russell Group institution, awarded 72% of its postgraduate places in 2010/11 to students outside the EU. The institution ranked number 92 out of 122 in the Sunday Times University League Table.
Of the international students coming to study in the UK, 64% went to a university, while one in eight went to a Russell Group university.
Migration Watch UK, who published the statistics, says the figures dispute the claim international students coming to the UK are "the brightest and the best".
"The vast majority attend institutions that are not considered to be in the top tier of learning in Britain," a statement on the group's website reads.
Buckingham University's non-EU students made up 49% of its undergraduate population. The proportion of international students rose significantly in postgraduate courses - with University College Birmingham, London Business School, Bedfordshire and Greenwich universities all having more than 50%.
A spokesman for the University of Buckingham told The Huffington Post UK: "We take care to establish that applicants admitted to Buckingham are legitimate, that they attend their classes, and, in the small number of cases where they fail to do so, are returned to their country of origin."
Of the top 10 UK universities, the London School of Economics (LSE) had the most overseas students, with them accounting for 48% of all students.
Commenting on the figures, Sir Andrew Green, chairman of Migration Watch UK said: "This report lifts the lid on what is really happening in the university sector. Non-EU students are being recruited to prop up the finances of less well known universities.
"It is time the strong public interest in immigration control was properly balanced against the self-serving pleading of the universities lobby in the UK which is in denial about the potential impact of foreign students on net migration."
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Universities UK's chief executive, Nicola Dandridge said universities are "tremendously diverse" and said international students took home degrees of real value.
"UK universities have a world-class reputation. Their strength and diversity play a central part in their success.
"Talented students from across the world want to study here because they know they can get high quality education from a variety of institutions.
"Our universities are tremendously diverse. It is to the universities' credit that international students hold them in high esteem, and that they can take home degrees and experiences of real value."
Earlier this month, a YouGov poll commissioned by the group found 70% of the public want to see a limit on the number of foreign students admitted to Britain. The issue is under close scrutiny following the London Metropolitan University saga, which saw the institution have its Highly Trusted Sponsor status revoked.
Pressure has been put on the government by the National Union of Students to exclude international students from immigration numbers as the current policies are "absolute rubbish".
Think tank the Institute for Public Policy Research (IPPR) previously warned David Cameron not to put short term political aims above overseas student immigration.