Talks are under way between ministers and Labour backbenchers about "clarification" of the higher education bill as it emerged that up to 20 vice-chancellors are poised to step up their lobbying against variable fees.
Government sources said there would be "no further concessions' on the bill but admitted that ministers were still talking to backbenchers about their concerns - particularly over plans to review the operation of the fee system.
It is understood that Labour MPs - including loyalists - are considering tabling "radical" amendments next week.
But the return of the bill to the Commons on March 31 after its scrutiny in committee may be greeted by a public letter signed by as many as 20 vice-chancellors outlining their "major concerns" about variability.
Ironically, 74 vice-chancellors signed a newspaper advert in support of the bill at its second reading in January.
But some vice-chancellors said Universities UK had failed to "adequately represent" the range of views about the bill.
UUK replied: "Any membership organisation is going to have a variety of views. The overwhelming majority of our members support the higher education bill and our position is clear - the proposals for a variable graduate contribution scheme, coupled with the enhanced measures for student support, are necessary and fair."
Michael Driscoll, chairman of Campaigning for Mainstream Universities, said: "I think that any organisation that represents a very diverse sector is going to have difficulty in reflecting all those views at the same time.
UUK has had a difficult job to do holding the ring, and no matter how hard it tries it is bound to be seen to have failed by one group or another."
- Tuition fees will hinder students from continuing their education, the National Postgraduate Committee has warned. The NPC will oppose the bill because of variable fees although it supports plans for an Arts and Humanities Research Council and wants the visitor system for dealing with student complaints scrapped.
THE FIVE WITH BIG RESERVATIONS
Gillian Slater of Bournemouth University
"The cap on fees will be lifted very rapidly indeed, and a small number of universities will be pushing to charge £10,000 to £15,000 a year. I don't think that would be a very happy scenario for public life in England - a very retrogressive step. We should do everything we can to get variability removed from the bill."
Malcolm McVicar of the University of Central Lancashire
"There is a group of us who are deeply concerned about aspects of the bill - supportive of much of the bill but deeply concerned at aspects such as variability. There are 20 or so who have major reservations: vice-chancellors and principals of large colleges."
Mike Thorne of the University of East London
"The issue is trying to get across our concerns adequately when we don't feel the representational body, UUK, is successfully doing that. We've all been talking long and hard to local MPs and those sympathetic to our point of view - which is that the government has moved, but not moved far enough."
Chris Taylor of Bradford University
"There are significant numbers of vice-chancellors, in my opinion, who are ill at ease about variable fees, and I think we still need a proper debate about the implications of a market economy at undergraduate level in higher education."
Simon Lee of Leeds Metropolitan University
(Objecting to Sir Richard's Sykes' comment that money was being "wasted" on "third-class" modern universities)
"The higher education bill is a Trojan horse that the government and its cronies have wheeled right up to the gates of universities. Beware cliques bearing gifts.
"Sir Richard Sykes has revealed what is really intended by popping out prematurely, in full warrior mode, launching an ill-informed attack."