A Scottish university is battling a tobacco giant's attempt to gain access to its research into the smoking habits of thousands of teenagers.
Philip Morris International (PMI), which makes Marlboro cigarettes, has submitted Freedom of Information (FoI) requests to Stirling University.
The research examines why the teenagers start smoking and what they think of tobacco marketing.
Academics said agreeing to the request would be a major breach of confidence.
They are also concerned it could jeopardise future research.
Prof Gerard Hastings, of the university's Centre for Tobacco Control Research, said: "It is deeply concerning they are even trying to get this data.
"We are talking about children and this is data the tobacco companies themselves would never be allowed to collect."
He said it would be "catastrophic" if the centre lost its fight and was forced to hand over the data.
"Most fundamentally this information was given to us by young people in complete confidence," he said. "We assured them we would treat it with absolute confidence and that it would be restricted to the research.
"There is no way that Philip Morris qualifies in that definition.
"It has enormous implications for academic freedom."
The centre, which is part of the university's Institute for Social Marketing, of which Prof Hastings is director, was established in 1999 by Cancer Research UK and aims to discover why children start smoking.
Over the past decade the study has involved up to 6,000 teenagers and young people aged 13-24.
The department initially refused even to respond to the request, complaining it was "vexatious".
But the information commissioner said on 30 June that this was not the case and also found the university had failed to respond to the request within the time limit.
The university said it had now made a "proper response" to Philip Morris, but is still refusing to hand over its research.
A spokeswoman for the information commissioner said the company could appeal again.
"If the commissioner comes to the decision that the university was not correct and has not applied the right exemptions, he can order the release of the information," she added.
A Philip Morris International spokeswoman said: "PMI made a Freedom of Information request to understand more about a research project conducted by the University of Stirling regarding plain packaging for cigarettes.
"Such government-funded research conducted by public institutions is covered by the Freedom of Information Act, in accordance with which members of the public can request information held by public authorities."
She added: "With regards to this FoI request, the Scottish Information Commissioner confirmed in his decision of 30 June, that we had a legitimate interest in seeking the information and asked the university to respond to the request.
"We are not seeking any private or confidential information on any individuals involved with the research. As provided by the freedom of Information Act, confidential and private information concerning individuals should not be disclosed."
The spokeswoman added that the commissioner also concluded that the information request submitted by PMI was not designed to cause disruption or annoyance to the university.