It is the biggest repercussion of the #MeToo movement in France: the influential Swiss-born academic Tariq Ramadan, a professor of contemporary Islamic studies at Oxford University, has spent the past nine months on remand in prison after two French women accused him of raping them in hotel rooms in Paris and Lyon.

Ramadan denies rape, the women stand by their allegations, but in recent weeks the case has increasingly played out in the public arena. Supporters of the well-known academic, who has spoken out against restrictions on the Muslim headscarf in France, say the justice system there is biased against him. They say the 56-year-old father of four is the victim of a conspiracy, has not been given due process and should not be on remand in jail, where he is being treated for multiple sclerosis in a hospital wing.

Lawyers for the Muslim women who accuse him insist it is a case of vulnerable women being raped by a powerful man.

Henda Ayari, 41, a former Salafist Muslim who is now a feminist activist, went to police last November and accused Ramadan of rape, sexual violence, harassment and intimidation. She said he raped her in a hotel room in the east of Paris in spring 2012 during a conference where he was speaking. “He choked me so hard that I thought I was going to die,” she told Le Parisien newspaper.

Another woman, known as Christelle, who is a convert to Islam and was left disabled after a car accident, later told police Ramadan raped her in a Lyon hotel room in October 2009 during another conference. Media reports have said her lawsuit describes blows to the face and body, forced sodomy, rape with an object, and being dragged by the hair to the bathtub and urinated on.

A third woman, in Switzerland, has since accused Ramadan of raping her in a Geneva hotel and a formal investigation has been opened.

Ramadan, who has advised successive British governments on Islam and society, denies all charges, saying his accusers are “compulsive liars”. Since February, he has consistently told police and investigators that no sexual encounters took place between him and the women.

But the inquiry took a turn last week when Ramadan changed his story, admitting to investigating judges that he did have sexual relations with the women, but saying they had sought the encounters and fully consented to the “dominant-submissive” relationship.

This change happened after computer experts extracted hundreds of text messages from an old mobile phone belonging to Christelle. Ramadan had earlier said he only met her in a hotel bar. But text messages from him – which have been quoted by lawyers and published in the media – give her instructions to come up to his hotel room. The text messages detailed Ramadan’s sexual fantasies of domination before the alleged attack. A leaked report prepared by computer experts working on the investigation shows he texted her after their encounter saying: “I sensed your unease … apologies for my ‘violence’”.

The texts are now the topic of a public row between the legal teams. Ramadan’s lawyer insists that the messages show Christelle was consenting, that she sent Ramadan many sexual messages and that one of them, sent on an unknown date, stated: “I missed you as soon as I left”.

Christelle’s lawyer, Eric Morain, said the messages were not dated, and that she could explain every message to the investigating judges. He said Christelle had been in contact with Ramadan for a period before the alleged attack.

“For 11 months, Tariq Ramadan has lied, and all that time he was calling the complainants liars and taking the judges to task,” Morain said. “His gamble – and it was a failed gamble – was to think it would be impossible for us to prove our case. His gamble was that my client wouldn’t be believed.”

Asked whether women had deliberately colluded against Ramadan, Morain said: “When a man is accused of rape by several women – even if he isn’t famous – it’s common for the man to claim the women have deliberately got together to damage his reputation. That’s a classic. But when you look at the disruption and devastation to a victim’s life – the police interviews, interrogations, questioning and so on – what would they have to gain from this? It has been 11 months of hell for my client.”

Ramadan’s defence have said they also found text messages sent by Ayari to Ramadan of an explicit sexual nature showing that she was consenting and wanted to have sex with him.

Ayari’s lawyer, Jonas Haddad, said he had submitted all available information on communications between his client and Ramadan at the start of the investigation. “We have nothing to fear. We just want this case to progress to trial.”

Ramadan’s lawyer, Emmanuel Marsigny, said his client was relieved to have told investigating judges that encounters did take place but were consensual.

Facebook Twitter Pinterest Emmanuel Marsigny speaks to journalists at court in Paris after Ramadan changed his version of events. Photograph: Yoan Valat/EPA

Asked why Ramadan had not said this from the start, Marsigny said: “Because he wanted to protect his private life, he wanted to protect his family. He had the feeling that, whatever was said, he’d be seen as guilty anyway – he felt as if he’d already been condemned by the media, which was engaged in Ramadan-bashing. By recognising the sexual relationships, he also now has the proof it was all consensual.”

He said Ramadan would file legal complaints against the women for slander and for making a complaint about “an imaginary crime”. He said he would appeal for the investigation to be dropped.

A fourth demand for Ramadan to be released on bail from prison pending trial has been lodged. Each previous request has been rejected by judges and appeal courts.

Meanwhile, the Swiss investigation into the third rape accusation is ongoing. A spokesman from the Geneva prosecutor’s office said preparations were under way to interview Ramadan.

Romain Jordan, the lawyer for the complainant, said his client was about 40 when she met Ramadan at a conference he organised. They exchanged messages on Facebook and Messenger then on 28 October 2008 he “insisted” they have coffee in a hotel on the Right Bank in Geneva.

“He was waiting in his room,” Jordan said. “But to drink a coffee, you don’t go up to someone’s room, so she refused. They had a coffee downstairs, then, after talking for a little, he asked her to help him carry an ironing board up to his room, saying that he had a television appearance the next day and needed to iron his clothes and suit. And as soon as they entered the room, it was a nightmare for her which lasted all night. She was raped and sexually assaulted.”

Ramadan’s Swiss lawyer declined to comment.

Ramadan’s French defence said there had been no complaints against Ramadan in the UK where he is on a mutually agreed leave of absence from Oxford University.