Kelechi Okafor said she was treated in a "degrading" and "vile" manner.

Barnett said she and her producers were discussing alleged anti-Semitic remarks Okafor had made in the past.

The host said she then raised these directly, adding: "I stand by my questions to my team and to Kelechi."

Barnett said Okafor "denied the allegations and hung up".

Okafor, who is an actress, dance instructor and podcaster, had been booked for an item about the #MeToo movement.

Wednesday's programme marked a year since the trial of disgraced film producer Harvey Weinstein, who was jailed for 23 years for rape and sexual assault.

The 15-minute discussion was intended to explore what the #MeToo movement has achieved.

After Okafor pulled out of the programme, the item went ahead with the other guests, Rosanna Arquette and Caitlin Dulany - two of the actresses who accused Weinstein of sexual assault.

Writing on Twitter, she said Barnett spoke about her in a disrespectful way, without realising she could be heard.

"The host didn't realise her mic was on as she was talking about me before the interview started," Okafor posted.

"You can have a genuine concern about something you've been told about me and address it in a manner that is kind. That wasn't what took place.

"The need for me on today's show was to offer balance to these wayward women thinking that the MeToo movement is no longer needed. The fact is that if you feel it's no longer needed for your white middle class sensibilities, marginalised voices still need it.

"We haven't heard from everybody regarding the violations they've faced. The originators of the MeToo movement were black women. From enslaved black women who were raped by slave owners to Tarana Burke yet their voices are yet to be honoured."

Writing on Twitter, Barnett said: "Just before I went on air this morning to present a special programme about Me Too... it came to my attention that one of our guests, Kelechi Okafor, had made alleged anti-Semitic remarks.

"I was also sent a press report of the transcript of what she had said on her podcast supporting Reggie Yates's comments about Jewish male managers and profits."

Yates apologised in 2017 after saying in a podcast interview: "The thing that makes it great about this new generation of [music] artists is that they ain't signing to majors. They're independent, they're not managed by some random fat Jewish guy from north west London, they're managed by their brethren."

Later that year, Okafor said Yates had been speaking "the truth" and said his comments were "not problematic".

Barnett continued: "As Weinstein is also Jewish and was referenced as part of this same podcast, I was discussing with my producers the role of this guest in light of her allegedly anti-Semitic comments. Kelechi overheard that chat on our open Zoom link - with two minutes to airtime.

"I then directly talked to Kelechi about the allegations, standing by my queries, and said she could put her response across in the programme. She denied the allegations and hung up, choosing to no longer be part of the programme.

"I stand by my questions to my team and to Kelechi. I would have happily hosted her on the programme with a question on this issue."

She added: "I believe people can always answer for themselves - but equally it is my duty to ask people what qualifies them as a leading voice in a space."

A BBC spokesman said: "During an off-air conversation ahead of the programme, Emma Barnett and the production team talked about a guest's role in the discussion, and how to reflect some of the guest's alleged previous comments and the issue of anti-Semitism as part of the Woman's Hour discussion on the role of minority voices in the MeToo movement.

"This was also raised directly with the guest before going on air."

The BBC said the off-air conversation did not make reference to Okafor's race.

The alleged incident occurred on Barnett's third day as the new presenter of Woman's Hour. Dame Jenni Murray and Jane Garvey both left the programme last year.

Barnett has previously spoken out against anti-Semitism on her BBC Radio 5 Live programme after controversial comments from the rapper Wiley.

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