Access to university should be based on ability to learn, not ability to pay, the prime minister, David Cameron, insisted earlier this month. Denying reports that the government would allow universities to recruit above their student number limit so long as the extra students paid higher fees, he was adamant. "There is no question of people being able to buy their way into university," he said.

But universities are already allowed to recruit extra students who pay higher fees – if those students are foreign. With students carrying more of the burden of funding in future, as home and EU tuition fees rise to up to £9,000, and with government support for humanities subjects being withdrawn, will foreign students become ever more valuable as cash cows?

"Most universities' costs are close to £9,000 or very nearly," says Les Ebdon, vice-chancellor of the University of Bedfordshire and chair of the university thinktank Million+. "Many people feel that by the time they have made provision for the spending required by access agreements and the abolition of the Hefce [Higher Education Funding Council for England] central grant, they will be getting less from home students than they are at the moment, so it makes them even more interested in the international market."

The average overseas student fee for 2010-11 was £11,435 – more than £2,700 higher than the average home/EU fee expected to be charged from 2012. Unlike for home students, there is no cap – Oxford, Cambridge and Imperial College, London, all charged more than £18,000 for lab-based subjects last year – and no obligation to ensure fair access for different social groups. Institutions can recruit as many international students as they like and recruitment is positively encouraged by the government as foreign students contribute an estimated £8bn in fees and other spending to the UK economy.