Teenagers from disadvantaged backgrounds are being offered places at some of Britain's top universities with lower grades than middle-class pupils, The Daily Telegraph can disclose.

Fifteen universities including UCL, King’s College, Exeter, Manchester, Warwick, York, Newcastle, Leeds and Liverpool have launched formal schemes where the applicants can get an alternative offer reduced by up to two grades below the normal required tariff, which is generally at least AAB. Birmingham is prepared to lower offers by up to three grades for medicine where students are typically offered A*AA.

Bristol also admitted almost 1,000 students on offers of up to two grades lower than the normal tariff for the first time last autumn and plans to expand its positive discrimination scheme to more pupils this year.

The schemes are likely to lead to renewed debate over how far universities should go to widen participation and accusations they are discriminating against teenagers from wealthier backgrounds.

Ministers have criticised universities for not doing enough to widen access to higher education but some education experts warn it will lead to a dumbing down of standards.