The report from the Knowledge Partnership draws upon University and Colleges Admissions Service (UCAS) data from 2008-2010, and covers all pre-university providers bar pathways linked to universities in order to explore the “open market” of international students in the UK. It does not cover direct applications by international students, which are not made public by universities.

The report suggests that students already studying in the UK – at further education (FE) colleges, independent schools or English language schools for example – are the “main source” of international undergraduate recruitment through UCAS for universities, accounting for 50% of the 200,000 applications made each year.

This dwarfs estimates of 10% to 20% made by some universities and would be nearer 59% had pathway programmes been counted, states the report.

“Universities may have focused resources on markets which were more familiar”

The report’s author, Sarah Beresford, said: “Until now there has been little available research undertaken on this market which would explain why some universities may have been unaware of its significance, or focused resources on markets which were more familiar.”

The report found independent schools to be the largest source of international students within the UK, providing around two-thirds of UK-based applications in 2010, followed by FE colleges, responsible for one-fifth.

Students from 13 of the top 20 country markets in 2010 were said to be more likely to apply from within the UK than overseas.

Those applying from within the UK were also said to be twice as likely to “convert” into enrolments due to their higher level of English, recognised qualifications and greater finances.

The findings will be welcomed by the UK’s pre-university sector. It faces pressure as the government makes it harder for private providers to recruit abroad by requiring them to obtain highly trusted sponsor status and meet other conditions.

Those applying from within the UK were also said to be twice as likely to “convert” into enrolments

Beresford said: “Given the proportionate size of the UK-based market to the UK undergraduate recruitment market as a whole, it would suggest that measures which artificially shrink market interest and recruitment at pre-university level study in the UK will have an impact on international recruitment at undergraduate level, because it will reduce the volume of applications applying to UK universities through this route,” she said.

Universities have also found the report cause for concern. Vincenzo Raimo, director of the International Office at the University of Nottingham, which recruits 25-30% of its overseas students onshore, said: “It’s good that there is increasing regulation in this area…to ensure that ‘rogue’ and poor providers are weeded out, but in doing so it’s vital that we don’t put the many excellent private providers out of business – they’re part of the UK student supply chain and vital to its success.”