The government has been warned that its policy of variable top-up fees could do grave damage to some universities.

In a letter to the Guardian, 15 vice-chancellors voice concerns about the policy of variable fees.

They warn that the system could result in elite universities becoming even more powerful as the less high acvhieving institutions fall further behind in the income stakes.

Ahead of tomorrow’s vote on the third reading of the government’s higher education funding bill, the university chiefs urge ministers to think again.

They say that the system will be to the "disadvantage" of the the majority of students.

"We recognise the need for graduates to make a contribution to their education. However, we believe that variable fees will further widen the differences in resources for universities and disadvantage the majority of students. We urge the government to reconsider its position on variability," they say.

Those who put their name to the letter include John Brooks of Wolverhampton University, Roger Brown of the Southampton Institute, Peter Fidler of the University of Sunderland and Michael Goldstein from Coventry University.

Meanwhile 12 academics working in higher education insistutions including including Cambridge, London South Bank, Gloucestershire and Sussex have also warned that the government has got it wrong.

The 12 signatories say: "Widening access is not about moving a few well qualified state school pupils around the system so that they can get into elite universities, but about working with partners in education, training, employment and the broader community to raise attainment and aspirations at school, and to develop opportunities for people requiring different modes of study - students who are mature, part-time or work-based."