Students from a range of universities are claiming they are being pressed to make falsely enthusiastic responses to an official satisfaction survey.
Staff at Kingston University were recorded telling students to falsify their ratings in the government-backed annual National Student Survey.
In response, hundreds of students have e-mailed the BBC News website claiming this is a more widespread problem.
The higher education funding council says the survey is not invalidated.
The National Student Survey, set up by the funding council (Hefce), provides a league table of student satisfaction - which is intended to be useful for young people choosing a university.
Endorsed by the government and funded by the taxpayer, it is part of the process of quality assurance in higher education.
Caught on tape
But an audio recording made at Kingston University revealed that staff were instructing students how to respond to the survey - and using it as a way of promoting a positive image rather than an honest assessment.
Hefce says that it knows of a handful of other cases where concerns have been raised about the student survey.
In response to the story about Kingston, hundreds of e-mails sent to the BBC from students and academics claimed to have seen attempts to manipulate the survey.
These include claims that lecturers were instructing students to submit only positive responses and that special talks were being held to sell this message.
"The message was practically shoved down our throats. Give us good reviews or your degree won't be worth much and you'll look like you're coming from a rubbish place in your interviews.
"We had at least three 'special' lectures on it, and a school wide announcement and e-mails and it was announced in induction events," wrote Brian from Newcastle.
"To a greater or lesser extent, this happens everywhere. At my university the reminders were constant and carried a threatening overtone," wrote Patrick from London.
"We were threatened by our university course leader: if you honestly answer the questions, you will suffer. He was suggesting if we aired our problems in the student survey the course would gain a negative reputation, thus: our qualification useless," wrote Lou.
A repeated claim is that students have been told that their future employment opportunities will be boosted by improving the university's reputation - and that the survey is a way of achieving this.
"We've been told several times that negative feedback will reflect badly on us and damage our career prospects," e-mailed Paul from Manchester.
"I'm sure all universities do it, I know mine did. We were told that if the university isn't respected then your degree will be worthless," wrote Keir from Sutton Coldfield.
But universities contacted have rejected the idea that there are widespread problems with the survey - or that students could be given advice on how to answer questions.
Hefce also defends the credibility of the survey.
"Apart from Kingston, a very small number of cases has been brought directly to our attention. Again each of these has been or is being investigated.
"They generally relate to a very small part of an institution's provision and the institution has dealt with the issues in a responsible manner," said a spokesman.
"We are confident that there is no evidence of systematic attempts to manipulate the survey outcomes by institutions," he added.
"We do not consider that the cases that have come to light call into question the robustness of the survey and believe that the great majority of students will take the opportunity to provide accurate feedback on their experiences," said the funding council spokesman.
But even though there seems to be a difference of opinion between the e-mailers and universities, there are academics who say that anything involving league tables will inevitably be linked to PR.
A student at Bournemouth University complained via the university's website that he had been disappointed to have a lecture interrupted to "pressurise us into rating the university well in the National Student Survey".
In response, the Dean of Business, Chris Brady, wrote of the survey: "What I said, and I am happy to stand by it, is that we need to work as a team to add value to your degree and that entails internal feedback and external PR."
Professor Brady says that his university does not influence how people respond to the survey, but he says that "anything that ranks anything has a PR element".