Universities have been told to enrol more students from disadvantaged groups or they could be ordered to cut their fees.
A report published today by the Office for Fair Access (Offa), the universities watchdog, finds that almost one in four universities – including five of the most selective in the country – have failed to meet their targets for widening participation.
It also shows the percentage of their income spent on boosting access fell from 25.8 per cent to 25.1 per cent last year, although in cash terms it rose by £50m.
The findings prompted David Willetts, the Universities minister, to warn: "Social mobility in this country has stalled. While universities have met their financial commitments to students, we need to see real progress in fair access, especially at our most selective universities."
The report warns it will be placing "greater emphasis" on universities meeting their targets in future. Offa has what it terms the "nuclear option" of refusing to allow universities to charge more than £6,000 if they fail to honour their access agreements. As a first step, they will be called in to a meeting to explain themselves over the next few months.
Offa has also made a significant change to its monitoring arrangements, requiring all universities to set at least one target for the recruitment of entrants from disadvantaged groups. In the past, it has merely asked them to set targets for applications.
Sir Martin Harris, Offa's director, said: "I think there comes a time when we have to move on from concentrating just on the applications pool. They will have to set at least one target for entrants – it could be poor students, disabled students or ethnic minority groups."
A breakdown of the 23 per cent of institutions that have failed to meet their targets reveals many are among the most selective universities. They include University College London, Bristol, Cambridge, Durham, Exeter and Warwick.
However, Wendy Piatt, of the Russell Group of leading universities, said: "A-level [and equivalent] results in the right subjects are more important than money in deciding whether a student will go to a Russell Group university."