Leading universities are offering places to disadvantaged students with A-level results three grades lower than middle-class teenagers.

       Fourteen universities are targeting children from disadvantaged families or poorer-performing schools with lower offers designed to recognise their academic potential rather than actual performance.

       Two universities - York and Lancaster - are offering places to such teenagers at three grades below their standard offers for entry this September, which could mean a reduction from AAA to BBB.

       The other 12 - including UCL, Exeter, Manchester, Warwick, Nottingham, Newcastle, Sheffield and Liverpool - also have formal schemes where pupils who fulfil the criteria can get offers two grades lower than the standard tariff in most courses.

       The schemes help universities meet their official benchmarks for state school entry but will renew debate over how far they should go to widen participation and potentially discriminate against teenagers from wealthier backgrounds.

       Private schools will get less Oxbridge offers

       It follows a warning by Professor Stephen Toope, Cambridge’s vice chancellor, that private schools must accept that they will get fewer students into Oxbridge.

       Prof Alan Smithers, the director of Buckingham University’s Centre for Education and Employment Research, said that attempting to assess potential on a “blanket” basis could discriminate against those with good A-level results, which were the best indicator of performance.

       “A-levels should be the focus and we should not be looking to balance up by ethnicity, gender, social class and types of schools people go to. You may be able to dig behind A-levels and assess potential on an individual basis but it is very hard,” he said.

       Nadhim Zahawi, the Education Secretary, shares concerns it could undermine the focus on high academic standards in some universities, although he accepts that there are cases that merit lower offers to take account of disadvantages such as being in care or a refugee.

       Mr Zahawi told The Telegraph: "Universities have an obligation to run fair admissions schemes and should not compromise on academic standards.

       "While it is right to consider each applicant as an individual, and talent can come in many different forms, one-size-fits all approaches based on a person's background are rarely the best way of doing this - and discriminating against a child because of their background or which school they went to is never acceptable."

       Students on the scheme more likely to stay on their course

       The scheme, known as Realising Opportunities (RO), is targeted at pupils from deprived areas with little tradition of sending students to university, who are entitled to free school meals or similar aid or are the first in their family to go to university.

       To be eligible for lower grade offers, pupils have to meet two of the criteria, complete an academic project and attend RO events. This year the scheme has been expanded to accept a record 1,298 students at the 14 universities.

       Supporters said that, once at university, RO students were more likely to stay on their course, at 91 per cent against a national average of 88.5 per cent. Some 86 per cent of RO graduates obtained a first or 2:1 degree, compared with a national average of 82 per cent.

       A spokesman for the scheme said: “RO works to address gaps that still remain in the system. Despite numbers increasing, students from disadvantaged backgrounds are still half as likely to progress to university as those from the most advantaged backgrounds.

       “Young people from advantaged backgrounds are currently over six times as likely to attend one of the most selective universities as those from the most disadvantaged areas.”