Duncan Smith accused the government of 'social engineering'

He said the government's higher education policy failed three tests - it was unfair, threatened the independence of universities and narrowed, rather than spread, opportunity.

Mr Duncan Smith repeated Tory promises to scrap the proposed access regulator, which will decide whether universities are doing enough to attract working-class students and can charge fees of up to �3,000 a year.

The comments come after The Headmasters' and Headmistresses' Conference (HMC) and the Girls' Schools Association (GSA) - representing private schools - said they would discourage pupils from applying to Bristol University.

They claimed it had "discriminated" against the fee-paying sector.

Mr Duncan Smith told students at King's College, London: "The government's plans and indeed the actions of some universities - Bristol being only the latest - are really only discrimination by another name."

'Fraught with danger'

Children from families with an income that was slightly too high for them to quality for the grants being restored next year faced leaving university with huge debts.

The access regulator, announced in the January white paper on higher education, was "fraught with danger", he added.

"We are all concerned about widening access but social engineering is the wrong way to deal with the issue."

Candidates from good state schools, not just private schools, would suffer, Mr Duncan Smith said.

He added: "What I find so extraordinary about this so-called access regulator is that he will be in a position to override accomplishments such as those which earned you your place here.

"He will be in a position to, in effect, reject a would-be student's application for admission on the grounds that his parents went to university.

'Orwellian'

"What it says to young people is, it's not what you know or have done that matters, but where you are from.

"It's perverse, it's positively Orwellian, it's the class system just stood on its head."

The best way of widening access to university was by improving state schools.

"We're not going to do it by rigging the admissions system or introducing quotas or punishing success. Only ability should matter."