Fewer than 1% of the poorest university students in England go to Oxford and Cambridge, the government's higher education access watchdog revealed today.
Last year, 2,024 students at Oxbridge received a full bursary – only eligible to those whose family income is £25,000 or less each year, a report by the Office for Fair Access found.
This is just 0.88% of the 230,289 students who claimed bursaries at universities in England.
In contrast, 10,827 students attending Liverpool John Moores University and the University of East London claimed a full bursary – 4.7% of the total for the whole country.
The watchdog released the figures in a report on how much universities spend on bursaries and scholarships for the poorest students.
A spokeswoman from Oxford said the university had "recognised for some time that we do not have as high a proportion of students receiving full bursaries as many other universities".
Oxford spends nearly £3m each year trying to encourage under-represented groups of young people to apply to university, she said. She added that the university offers one of the most generous bursaries in the country, providing £10,550 over three years compared with the sector average of £2,940.
The watchdog calculated how much of the extra income that universities receive from charging fees is spent on recruiting and encouraging poor students to take up places. The extra income is the additional money that universities receive per student for charging over £1,225 in fees.
On average, universities spent 25.8% of their additional income on bursaries and scholarships for the poorest students and "outreach" activities encouraging deprived pupils to consider going to university, the report found. The year before last they spent 25%.
The report found that while some universities spend as much as 45% on the poorest students, others spend less than a fifth. Southampton and Sheffield universities spent 17.5% and 19% respectively. Cambridge spent 25%, while Oxford spent 31%. Thames Valley University spends 45.4% of its additional income on bursaries and scholarships.
The findings prompted the National Union of Students (NUS) to accuse university leaders of "greedily" keeping their fee income to themselves, rather than spending it on deprived youngsters.
"The regulation that surrounds the charging of top-up fees is farcical and has allowed greedy university heads with the worst record on access to ask for huge student contributions and spend less on outreach than those with a better record at getting poorer students onto their courses," said Aaron Porter, NUS president.
However, the watchdog pointed out that universities with a smaller pool of poor students would only be able to give out a smaller sum in bursaries and scholarships than those with large numbers of deprived young people.
The report shows that the proportion of the poorest students who are claiming bursaries and scholarships has jumped to 96% of those who are eligible. About 90% of those eligible were claiming one in 2007-08. Just over 346,000 students from low-income families claimed a bursary last year, and 70% of them were eligible for the maximum sum.
Universities can decide how much they give to the poorest students as bursaries and scholarships. On average, they awarded £980 for the full bursary.
The lecturers' trade union, the University and College Union, said the amount a poor student received as a bursary had become a lottery that was determined according to where they studied.
Sally Hunt, UCU's general secretary, said it was "ludicrous that students' financial aid is decided in such a random and unfair way".
The union is calling for a nationally set bursary scheme.
But the Russell Group said this would create many losers and few winners. "There would be relatively small increases to a standard bursary, but many high-achieving, low-income students would lose out," Wendy Piatt, director general of the Russell Group, said. She added that if universities were allowed to charge higher fees, "this would provide them with more resources to recruit and support students from under-represented groups".
An independent review is looking into whether tuition fees, currently at £3,225 a year, should rise. It will report this autumn.
David Willetts, the universities minister, said students' awareness of bursaries "remained an issue". "All students must have the fullest possible information on which to base their choices and decisions about courses and institutions, including details of the financialsupport they can expect to receive."