Dr John Marenbon, a fellow of Trinity college, Cambridge, makes the comment in a pamphlet published by the right-of-centre think-tank Politeia. The claim comes only days before Tuesday's crucial House of Commons vote.
Dr Marenbon argues that "good universities" would benefit from being able to charge variable fees, particularly if they could charge more than the maximum pound;3,000 proposed.
"In Britain, academic excellence has traditionally been fostered, both at school and higher levels, by independent institutions," he said.
"Where government has intervened and taken more direct control, the decline into mediocrity has usually been rapid."
As The TES went to press, education ministers seemed confident of winning next week's vote on fees. Growing numbers of the 160 "rebel" Labour MPs have switched support to the Government.
Analysis 19 Platform 21
University Challenge: Freedom, Fees and Future Funding by John Marenbon will be published on www.politeia.co.uk