An Oxford University professor whose invitation to a conference celebrating women was withdrawn has defended her stance on transgender rights issues.
Selina Todd was "no-platformed" by the Oxford International Women's Festival, at which she had been due to speak.
Prof Todd said she was told by the event's organisers the decision was due to pressure from trans activists.
The St Hilda's College academic said she "refuted" the allegation she was transphobic.
Speaking to the Emma Barnett Show on BBC 5 Live, Prof Todd said she had warned organisers that trans activists had threatened to disrupt events she had been involved in previously.
She said there were groups of people "who just refuse to engage in civilised debate" and insist they will not appear with someone with her views.
Feminist writer Lola Olufemi dropped out of the event, citing issues with campaign group Women's Place UK (WPUK), an organisation with which the professor is involved.
She tweeted: "TERF [trans-exclusionary radical feminist] links cut across universities, women's services and public institutions. They have no place in my vision or understanding of the political possibilities that feminism offers us."
'Cannot condone no-platforming'
WPUK was recently described as a "trans-exclusionary hate group" by the Labour Campaign for Trans Rights.
But Prof Todd told Barnett that the organisation was not transphobic and welcomed transgender people to its meetings. She said she was "enormously impressed" with the courtesy shown to transgender people who attended a meeting she was at last year.
She said "transwomen should be allowed to call themselves transwomen" but that in certain circumstances "we do need provision that differentiates on the basis of sex". She said that, for example, those born male have a risk of getting prostate cancer, and it was important to be able to get hold of the right people for screening.
The professor of modern history added: "I'm not saying that we shouldn't debate a change but in democracy you debate, you don't seek to close down the other side."
The collective Feminist Fightback, which Prof Todd said she had been told had put pressure on the event's organisers, said it only learned that she would not be attending while it was meeting to discuss whether it wanted to continue to participate.
It said in a statement: "The question from us was never whether we were opposed to Selina Todd's views (we are)... [but] whether continuing to participate in a conference at which she was one of the many speakers would make us complicit in those views".
In January, Prof Todd revealed she had been given protection at work after receiving threats from transgender rights activists.
Those behind the conference have not said why Prof Todd was excluded from the event at Exeter College on Saturday. The college said it had had no role in decisions about the programme or its speakers
The Oxford University History Faculty said: "As an academic department, we simply cannot condone the no-platforming of people who hold and express lawful views."
Kiri Tunks, from WPUK, said: "We are appalled that the Women's Liberation at 50 event disinvited Selina Todd.
"We are astonished that it is Selina Todd's association with WPUK that has been cited as the reason.
"We are honoured to be associated with her and we are all lucky that she is at the centre of the women's liberation movement today."