Stock’s resignation comes three weeks after a protest by some students at the university’s Brighton campus, which included posters and graffiti calling for her dismissal.

She has said she believes gender identity does not outweigh biological sex “when it comes to law and policy”, and that people cannot change their biological sex.

In an email to staff, Adam Tickell, Sussex’s vice-chancellor, said: “We had hoped that Prof Stock would feel able to return to work, and we would have supported her to do so.

“She has decided that recent events have meant that this will not be possible, and we respect and understand that decision. We will miss her many contributions, from which the university has benefited during her time here.”

Stock tweeted that she was sad to leave: “This has been a very difficult few years, but the leadership’s approach more recently has been admirable and decent. I hope that other institutions in similar situations can learn from this.”

She added: “This has been an absolutely horrible time for me and my family. I’m putting it behind me now. On to brighter things soon, I hope.”

A university spokesperson said: “Over the past several weeks, the University of Sussex has vigorously and unequivocally defended Prof Kathleen Stock’s right to exercise her academic freedom and lawful freedom of speech, free from bullying and harassment of any kind.

“These freedoms and protections apply to and benefit us all, and we will defend them today and in the future. Rather than conflicting with our progress on equality, diversity and inclusion, these freedoms and protections are in place to support those with protected characteristics, particularly those who are under-represented or disadvantaged.

“Universities must remain places where everyone – staff or student – has the right to, and benefits from, lawful freedom of speech.

“The university has been consistent and clear that everyone in our community has the right to work and learn, free from bullying and harassment of any kind, which has not been the case for Prof Stock.

“There were no substantive allegations of wrongdoing made against her. Prof Stock leaves the University of Sussex with our gratitude for her significant contributions as a teacher and academic. Prof Stock’s successes in the field of philosophy have been of great benefit to the university. Her departure is a loss.”

Michelle Donelan, the universities minister for England, said: “It is absolutely appalling that the toxic environment at the University of Sussex has made it untenable for Prof Kathleen Stock to continue in her position there. No academic should ever have to fear for their personal safety.”

Posting on Twitter, Donelan later asked “that universities come forward and offer [Stock] a suitable position in their own faculty – we must stand up for free speech”.

An Instagram account claiming to represent trans students at the university posted: “Massive win for Sussex LGBTQ+ students today … Let’s take a minute to appreciate this.”

Earlier this month Stock said she had been told by police to stay away from campus, and feared her 18-year career at the university had been “effectively ended” after the Sussex branch of the University and College Union called for an investigation into institutional transphobia.

After the protest against Stock, Sussex University students’ union said: “Students have a right to protest when their rights are being questioned, or when there are discriminatory narratives about them being shared.” It said that trans and non-binary students had complained of feeling threatened and lacked support from the university.

Labour MP Taiwo Owatemi, the shadow equalities minister, had also entered the controversy after saying she was “concerned” by Stock’s role as a trustee for the LGB Alliance – which campaigns for rights based on sexual orientation rather than gender identity. But Owatemi stressed that she “was not passing judgment on Prof Stock’s academic work, and did not call for action to be taken against her”.

The philosophy professor was awarded an OBE in the 2021 new year honours list for services to higher education.

But hundreds of academics criticised the decision, signing an open letter that criticised Stock’s comments on transgender and gender non-conforming people.

The letter claimed her “harmful rhetoric” about transgender and gender non-conforming people reinforced “the patriarchal status quo”.

“Academic freedom comes with responsibility; we should not use that freedom to harm people, particularly the more vulnerable members of our community,” the letter added.

“Conflating concern about the harms of Stock’s work with threats to academic freedom obfuscates important issues.”