Police asked a university to hand over a list of members of the public who were due to attend a public debate on its campus.

Canterbury Christ Church University, which had invited experts to debate the merits of fracking in an open forum, refused to hand over the list, and the police request has drawn sharp criticism, with one of the panellists branding it deplorable.

More than 200 people went to the debate to listen to and question a panel that included a retired geologist, engineers, a local councillor, an analyst from a thinktank and a campaigner.

Kent police said they needed to assess “the threat and risk for significant public events in the county to allow it to maintain public safety”.

The fracking debate on 19 November was organised by sociology academics, and members of the public who wanted to attend were required to book a place through the university.

The university confirmed that it had been “contacted for a list of attendees at the Engaging Sociology event, Fracking in the UK, and did not disclose the requested information.” It added, without further explanation, that “the university did not feel it was appropriate to provide the information”.

The request follows disclosures that police have been monitoring political activities at universities around the country, and spying on groups that use non-violent methods to further their aims. Last year it was revealed that police attempted to recruit an activist to become an informant and pass on information about Cambridge University students and other protesters.

At Lancaster University, police took photographs of two posters reading “Not for Shale” and “End Israel’s attacks on Gaza” in the office window of the students’ union president. They told her she was potentially committing a public order offence.

One of the panel at the Canterbury fracking debate was Ian Driver, a Green party councillor in Thanet, who has no criminal record. Last year he discovered that his political activities had been monitored and recorded by the police. Documents revealed that police had logged 22 occasions on which he helped organise public meetings and demonstrations about animal exports and gay marriage between 2011 and 2012, after he had been elected a councillor.

He said he was “astounded” when he learnt that police had requested the Canterbury list. “It’s deplorable. This was a public debate. It was not a meeting planning any actions, protests or demonstrations. It was simply a public discussion about a controversial issue,” he said.

A spokesperson for the University and College Union, which represents academics, said: “Academic freedom is a key tenet of our democracy and rightly cherished by our universities. We are extremely uncomfortable with the police asking for details of people intending to attend a public meeting.

“Universities must remain a safe space for students, staff and guests to rigorously debate any issue and not fear that the police, or any other Big Brother figure, is looking over them knowing who they are and where they live.”

Kent police said it had been “in contact with the event organisers” in November but declined to give further details.

Asked why it had requested the list, the force said: “Kent police assesses the threat and risk for significant public events in the county to allow it to maintain public safety and appropriately allocate resources. Police attendance was not required during the meeting, but the Dover district chief inspector did attend the event as an interested stakeholder.”

They declined to explain why the inspector would be an “interested stakeholder”.