The Home Office has refused to provide evidence as to why it named Kingston University on a shortlist of universities promoting extremism.

David Cameron’s office listed the university as one of four that had given a platform to extremists last month – but Downing Street is yet to substantiate the claims.

Faisal Hanjra, a trustee at Kingston Mosque, said: “It’s important that the debate surrounding extremism is evidence-based.

“So if the Prime Minister and his officials are making serious allegations, they must have evidence.

“On such a massive issue the onus must be on the Government and various officials to really substantiate what they are saying.”

A No 10 spokesman refused to elaborate on the evidence.

He said information “came from various sources”.

John Azah, chief executive at Kingston Race and Equalities Council, said: “If David Cameron is so concerned about Kingston University and the Kingston community in general, he and some of his colleagues ought to come and visit the university to see what positive things it is doing, rather than this unfair degrading of this really fine university.

“It has never, it does not, promote any type of extremism and it works very hard to ensure that there is freedom of speech.”

The university has 12 student faith societies, which host various speakers throughout the academic year.

Kingston University has also queried what led it to be tarred with the same brush as King’s College London, University of London's Queen Mary and the School of Oriental and African Studies (SOAS), said to have collectively hosted at least 70 events involving extremist speakers, Government documents claim.

Professor Julius Weinberg, vice-chancellor at Kingston University, said: “We have written to the Home Office to ask them to substantiate and clarify their claim. We have yet to receive an answer.”

Kingston and Surbiton MP James Berry said he could only assume the information came through the Metropolitan Police Service and has written to the Met.

He said: “I’m surprised. I would just like to know why Kingston has been connected, and what the university can do to get off the list.”

The chancellor of the university, Bonnie Greer, said she had not heard about the Prime Minister’s declaration of extremism at Kingston, but said she and the university were not worried.

Jokingly she tweeted: “Cam must be referring to my graduation ceremony speeches.”