Liberal Democrat MPs could be "emboldened" to follow Sir Menzies Campbell's example and vote against any increase in tuition fees in England, the party's former leader has said.
Sir Menzies, who is chancellor of the University of St Andrews, told Times Higher Education that a number of his Lib Dem colleagues shared his view that he would "lose all credibility" by reneging on a pre-election pledge on the issue.
The party's position has been superseded by the coalition government agreement struck with the Conservative Party, which leaves Lib Dem MPs free to abstain from any vote to increase fees but not to vote against a rise.
Sir Menzies' comments came as simmering political tensions over fees, university places and funding boiled over after David Willetts' first major speech on the sector.
Speaking at Oxford Brookes University last week, the universities and science minister said that Labour had left higher education on "shaky financial foundations" and indicated that supply-side reform was a necessity.
However, Mr Willetts' key messages were almost drowned out by a row over his comments in the national press that the cost of degrees was a "burden on the taxpayer".
The remarks were seized upon as evidence that the Tories will endorse any recommendation to raise the fee cap made by the ongoing funding review led by Lord Browne of Madingley - a potential coalition-wrecking issue.
Simon Hughes, the new Lib Dem deputy leader, said his party's voice would be "loud and clear" on fees, and although he made no suggestion that Lib Dem MPs would vote against the government, there is a growing feeling that some will break ranks.
Sir Menzies told THE he could not ignore the pre-election National Union of Students pledge, signed by all Lib Dem MPs, to vote against a rise in fees.
"I think it would drive a horse and cart through my credibility in my capacity both as chancellor and as an MP if I were to renege on that pledge - and I don't intend to," he said.
"I haven't done a headcount ... but I think a number of colleagues have expressed informal sympathy with my view."
He added: "I think it is up to them, but often people are influenced by the example of others, or even emboldened by the example of others."
Meanwhile, Mr Willetts' analysis in his speech of the sector's predicament won praise from many, but there was also puzzlement over his suggestion that teaching and examinations could be separated, in a similar vein to schools.
Mr Willetts said that allowing institutions to use external-exam "brands" would drive up teaching standards while benefiting "new entrants".
Alice Hynes, chief executive of GuildHE, responded that "existing providers are ready and willing to teach more students in a variety of settings, were current constraints lifted".
Others said that such a separation would require close attention being paid to quality.
Martin Bean, vice-chancellor of The Open University, warned against adopting simplistic solutions to complex problems.
"I think what we're really looking at here is better engineering the system to allow for high-quality teaching and learning as well as flexible pathways, because otherwise all we will have done is move degrees around," he said.