The National Union of Students (NUS) estimates this will be the amount owed by most graduates if the government raises maximum annual tuition fees to �3,000 from 2006.

For the survey, the NUS interviewed 15 to 16-year-olds, who would be the first group affected by the change.

It also found a third would not go to university if debt were �2,000 a year, rising to 60% if it reached �5,000.

Judith Watson, co-author of the report said: "It will be a great pity if young people with high aspirations are put off university by rising fees and debt.

"We are right to be concerned by the government's funding proposals."

'Extremely worrying'

A government white paper published in January set out plans to raise tuition fees from the current �1,100 a year to a maximum of �3,000.

The NUS estimates some students could leave university owing �30,000, as they also have to borrow to pay living costs.

But the government says higher fees are necessary to get "towards 50%" of young people into higher education by 2010.

Higher education minister Margaret Hodge said: "The NUS should stop trying to frighten future students.

"The latest Unite/Mori poll in to student attitudes show that 96% think university is a worthwhile experience and 87% think it is a good investment in their future.

"Future students should look at the new package as a whole.

"We are getting rid of unpopular upfront fees for everyone, we will continue to pay the first �1,100 of any fees for students most in need, we are re-introducing grants of up to �1,000 a year and we are increasing the repayment threshold to �15,000.

"Those with higher education qualifications earn on average 50% more than those without and this is the most generous form of credit you will ever get."

But NUS president Mandy Telford said: "Fees and debt will deter the very students the government wants to attract to university.

"It is extremely worrying that 85% of school children would not go to university if the government goes ahead with its plans.

"If the government is genuinely committed to opening up education then it must remove the threat of top-up fees and debt.