America has long reigned supreme as the most popular destination for international students.
But its dominance over second-placed Britain may be based on less solid foundations than previously thought.
A fresh look at the official data by the British Council suggests that the UK may have almost 125,000 more international students than the records traditionally show - giving the UK well over half a million overseas students and putting Britain much closer to America's figure of 623,800.
"We have believed for some time that we have many more international students in our universities and colleges than were being counted," said Pat Killingley, the British Council's director of higher education.
"Now we can see that the UK is challenging the US, the global leader in the market for international students."
The official sector data on overseas student numbers is traditionally based on the country in which students were living when they made their application.
However, the Higher Education Statistics Agency also collects data on the nationality of students. If this information is used instead, it gives a headcount a third higher than estimates based on domicile alone, the council said.
The dramatic difference has been put down to the number of foreign students who give a UK address when they apply to university, perhaps because they are already in the country studying an English-language or foundation course or are attending a boarding school.
The British Council claims that many of these students were previously classed as home students even though they paid hefty international fees.
In the past academic year, 2007-08, there were 389,330 international students here on the basis of domicile figures, but 513,570 on the basis of nationality.
The US had 623,800 overseas students last year.
Counting by nationality, the number of Nigerian students in Britain almost doubles to 21,000, and the number from Zimbabwe increases fourfold to 9,800.
The figures also increase from 49,000 to 55,000 for Chinese students, and from 28,000 to 35,000 for Indian students.
Despite the British Council's claims, Malcolm Gillies, vice-chancellor of City University, London, said the picture was "murkier" than the statistics suggest.
"The passport that you hold - and you may well hold more than one - is not a sufficient determinant of whether you are an 'overseas' student or not," he said.
He added that the figures that were important to institutions - their own international student numbers - were recorded in many different ways.
"At City we distinguish carefully between UK and other European Union students as they are subject to different marketing strategies, even if they may happen to pay the same fee," he said.