Proposed legislation on fees was included in the Queen's Speech

The Solicitor General, Harriet Harman, announced the revised figure on the BBC Radio 4 programme, Any Questions?

The shadow health and education secretary, Tim Yeo, said: "It was �15,000 when we came on air, it's now �18,000. Well, that is progress."

Challenged on the issue, Ms Harman double-checked her briefing note and confirmed the figure.

'No change'

Her only correction to her previous comments was to adjust slightly the repayment amount.

She said: "I was just anxiously checking as to whether I've got it right.

The detail is so complex that ministers' job of explaining it is about as easy as teaching algebra to five-year-olds The BBC's Mike Baker Are fee plans too bold?

"I have to say I've not got it entirely right: you won't pay until you reach �18,000 but then when you reach �18,000 you will pay �5.19p - so I was 19p out - a week."

But a spokesperson for the Department for Education and Skills said later: "The position is that under the proposals in the White paper you don't start paying back until you are earning �15,000."

This had not changed, she added.

The government is expected to begin its attempt to convert its proposals into legislation in the coming week - in the face of considerable political opposition, not least from its own backbenchers.

'Affordable'

Her argument had been that higher fees would not deter people from going into higher education through fear of debt.

GOVERNMENT PLANS Means-tested �1,000 grants from 2004 Upfront tuition fees end 2006 Fees then vary - up to �3,000 a year First �1,125 subsidised for poor Payable from graduate salary of �15,000+ Zero-rated student loan up to �4,000 a year New access regulator Teaching-only "universities" Research funding for the elite 50% participation through foundation degrees

"There shouldn't be any deterrent for people who fear they can't afford to pay, they won't pay until they've left university, until they can afford it," she said.

"And I think the problem is that 40 years of free education - what's that done except seen the gap widen, it has not seen working class children, children from families where nobody's gone to university, going into university."

Mr Yeo joked that a concession had been wrung out of the government by the "eloquence and passion" of the president of the National Union of Students (NUS), Mandy Telford, who was also on the programme panel.

Ms Telford said the NUS believed there would be a deterrent effect.

"Let's be clear: top-up fees means a market in our higher education system, it means some universities will be able to charge more for their degrees than other universities," she said.

All children who could benefit from higher education should be able to - but would either be put off from even applying or would choose cheaper courses, rather than the one they had dreamed of and studied hard for.