The University of Essex has apologised to two female academics who were prevented from speaking at campus events because of their views on gender and trans rights.
Professor Jo Phoenix was invited to speak at a campus event in December 2019 on trans rights and the criminal justice system, but her invitation was withdrawn after critics complained that she was a "transphobe".
Professor Rosa Freedman had been asked to take part in a panel discussion in January 2020 on the topic of antisemitism, but the university decided against sending her a formal invitation because of her views on gender identity.
Following an independent review by barrister Akua Reindorf, the university now admits "serious mistakes" were made in its treatment of the women.
The final report called the university's actions "unnecessary and disproportionate", and said there was no evidence that the two academics would say anything unlawful.
"In the context of the systemic and decision-making failures which led to it, the cancellation amounted to a breach of Prof Phoenix's right to freedom of expression and the associated legal duties to which the University was subject," the final report says.
"The later decision to exclude and blacklist Prof Phoenix was also unlawful. There was no reasonable basis for thinking that Prof Phoenix would engage in harassment or any other kind of unlawful speech. The decision was unnecessary and disproportionate."
It especially criticises the university's failure to investigate a flyer that contained a violent threat against Prof Phoenix.
"Moreover the violent flyer was wholly unacceptable and should have been the subject of a timely disciplinary investigation," it said.
Of Prof Freedman, the report said it was "plainly not necessary" to exclude her from the panel and that there had been "no reasonable basis for anybody to think that she would say anything unlawful about gender identity, not least because the topic of the debate would not entail any discussion of gender identity issues".
"Even if it had, there was no evidence that she might engage in unlawful harassment or 'hate speech' or other unlawful activity," the report said.
"There was no question of the University's duties under the Public Sector Equality Duty being brought into play; the mere presence on campus of a person with whom others disagree about gender identity does not indicate a failure on the part of the University to pay due regard to the needs to eliminate discrimination and foster good relations."
Elsewhere, the review uncovered evidence of a "culture of fear" among members of staff whose views on gender "deviate from the majority opinion in support of the trans rights advocates".
"This may also indicate that the academic freedom of these individuals is being inhibited," the report said.
Responding to the findings, Vice-Chancellor Professor Anthony Forster said the report "makes clear that we have made serious mistakes and we need to do our very best to learn from these and to ensure they are not repeated".
"The review notes the particular responsibility placed on universities to protect freedom of speech within the law, and to ensure that a diversity of voices and views can be heard on our campuses," he said.
"On behalf of the university, I have issued an open apology to each of Professor Phoenix and Professor Freedman."
He continued, "We must re-commit to providing a supportive and inclusive environment within which people can expect to learn, grow and develop through challenge.
"As a community this means that we may encounter ideas or arguments which may be experienced as objectionable or offensive; with a line drawn at conduct which is unlawful or contrary to the university's policies.
"On behalf of the university, I am offering an open apology to staff and students regarding the procedural and other failings that have occurred in relation to the two events covered in the Reindorf Report, and for any distress caused."