The case of a black university professor who resigned from his role at the University of Cambridge will provide those who condemn diversity and equality initiatives with a "weapon" and deter other black scholars from the field, academics have said.

Professor Jason Arday quit his high-profile position on Wednesday after the University of Cambridge launched an investigation into his "academic qualifications and honorary appointments".

This followed media reports alleging plagiarism of his PhD thesis, completed at Liverpool John Moores University, and other research.

The professor of sociology of education, who became Cambridge’s youngest black professor in 2023, also faced press scrutiny over claims such as running 600 miles in six days and raising £5.5 million for charity.

Adding to the furore, the Metropolitan Police has drawn criticism over its investigation into a harassment claim against a Times Higher Education journalist, who had emailed Professor Arday with questions some months ago.

Commissioner Sir Mark Rowley told LBC on Thursday that the force “dropped the ball on that one” and the report should have been “screened out earlier as not requiring investigation”.

Alan Lester, professor of historical geography at the University of Sussex, posted on social media last month defending Prof Arday from allegations by another academic, Nathan Cofnas – who has reportedly defined himself as a “race realist” – who claimed to have found instances of plagiarism in his work.

On Thursday, Prof Lester told the Press Association: “I trusted the investigations that Cambridge & Liverpool John Moores suggested they had launched into the plagiarism claims and disregarded the wider claims about his tall tales as it was the attempt to discredit his scholarship that concerned me.

“However, as it became clear that the plagiarism claim did not seem to have been investigated robustly, at least not by Cambridge, and that he had told more than just tall tales, I retracted, admitted I was wrong and apologised.

“The tragedy is that this case now provides the far-right racists who condemn any equalities and diversity initiatives with a weapon that they will wield egregiously.”

Kehinde Andrews, who was until recently professor of black studies at Birmingham City University, told Sky News the reason Prof Arday has received so much scrutiny is because there is an idea that he is a “DEI (diversity, equity, and inclusion) hire” which he called “ludicrous”.

“No one’s handing out favours to black people in higher education, and that idea is deeply dangerous and deeply racist,” he said.

“There is a whole campaign to get more black professors in, but the experiences that we have tend to be horrendous and it does put people off from trying to even get into these places in the first place.”

Prof Andrews was one of the signatories of a letter which criticised the “sustained and malicious attacks” on the academic’s integrity, alongside Green Party leader Zack Polanski.

Defending his decision to put his name to it, Mr Polanski told LBC: “(The university) had already done, I think, two investigations and found there was no problem here or that the allegations were unfounded, and so (the letter) was about essentially saying that people of colour, particularly in society, can sometimes be held by higher standards.”

An investigation at Liverpool John Moores University cleared Prof Arday of wrongdoing.

Cambridge University announced a probe on Wednesday, with Jesus College also saying it was launching its own process in relation to the allegation.

Prof Arday said in his open resignation letter that the “only way to bring this chapter to an end is to step away”.

In the letter addressed to colleagues published on the Good Law Project’s website, he said: “This decision should not be interpreted as a loss of faith in scholarship or in the values that first brought me to Cambridge.

“Nor should it be mistaken for an acceptance of the narratives that have surrounded me.

“It is simply the decision of someone who has reached the limits of what any person should reasonably be expected to endure.”

Prof Arday’s memoir, Great And Unfortunate Things, is due to be published by Simon & Schuster later this month.