The Liberal Democrats have claimed that students will graduate with a total debt of £14 billion in just six years time.

On the day the government's Higher Education Bill was set to pass through parliament, introducing top-up tuition fees of up to £3,000 from 2006, the party's education spokesman published figures showing the huge levels of borrowing that will be required to fund the expansion of student places.

Phil Willis extrapolated official statistics by the expected rise in university numbers by 2010 to come up with the headline grabbing £14 billion figure.

He said there are expected to be 1.47 million undergraduates in 2010/11, of whom 425,659 will graduate.

With Barclays Bank estimating that the average student debt could be as high as £33,000 by then, the total borrowed by the class of 2010 would be two times what the government expects to spend on higher education next year.

Ministers believe that graduate debt will become more manageable under the new regime, with repayments means tested and spread out over a longer period of time.

They also point to research showing the dividend of up to 40 per cent degree holders can expect to receive in their salary over the course of a career.

However Willis argued that the data highlighted the dangers in the Bill.

"This figure is shocking. Higher education should be about ability to learn, not ability to pay," he said.

"Today's decision on top-up fees will leave students graduating in 2010 with a debt twice the size of the government's budget for higher education this year.

"Fees equal debt. As fees increase, so will the number of students being forced to take desperate measures to pay off their debt.

"For the first time in four years the intake of working class students into our universities has not increased.

"Once again higher education is about to become the province of the wealthy, as real fear of debt will keep low and middle income families out of universities."