The National Union of Students has called for statistics to be kept on how many students are being "priced out of education" by tuition fees.

It claims tens of thousands might be each year - but there is no accurate count.

In evidence to the Commons education select committee's inquiry into student retention, the NUS said one in three of those who had to pay tuition fees received no parental help, with the average shortfall being �719.

But the Higher Education Funding Council for England said the main reasons one in five students dropped out of higher education each year were academic.

NUS representative Lindsey Fidler said university hardship funds were not currently available to help students pay tuition fees.

'Weak A-levels'

So many used their student loans, intended as living expenses, to pay their fees.

Professor Claire Callender, of South Bank University, who compiled a report on the subject for the Department for Education, said that the 360,000 students who dropped out each year cited debt as their main reason.

But the funding council said in written evidence: "Entrants with weak A-levels or non-A-level qualifications are less likely to complete."

Less than 2% of students with three A grades dropped out in their first year, compared with 14% with three Ds.

Drop-out rates for students from disadvantaged backgrounds who achieved high grades were very similar to those of higher social classes.

Data not yet in

The funding council's policy director, Bahram Bekhradnia, told the MPs that data for the period in which the abolition of grants began to bite were not yet available.

He said debt "might be a second order issue", but added: "I think on the basis of the analyses that we've done so far it seems we can explain drop-out to a very large extent by academic factors."

The NUS president, Owain James, said: "Thousands of students are being priced out of education.

"This is a national problem and the numbers revealed so far are merely the tip of the iceberg.

"Students who the government claims are able to afford fees are relying on funds for food and rent to cover the cost of a higher education."

Last week, the vice-chancellor of Sheffield Hallam University, Professor Diana Green, told the committee the number excluded for debt there had risen 17% since 1998, when fees were introduced, and fee-related debt had trebled.

There was "some evidence" that the same thing was happening at other universities in the UK, she said.