Women's rights activists are being forced to kiss and perform sex acts on their interrogators in jails in Saudi Arabia, according to a shock new report.

Inmates were also made to watch pornography, threatened with rape, hung from the ceiling, beaten and suffered electric shocks during treatment which "amounted to torture".

According to Daily Mail, in a 40-page report, human rights lawyer Baroness Helena Kennedy called on nations to boycott this weekend's G20 summit hosted by Saudi Arabia unless the women are set free.

Among a litany of abuse meted out to the prisoners, she included:

'Forcing the Women's Rights Activists to perform sexual acts on the interrogators, and other forms of sexual harassment such as forcing them to watch of pornography.

'At least one source reported that Aida Al-Ghamdi had been forced to watch pornography, and several sources reported that Loujain Al-Hathloul and Eman Al-Nafjan had been forced to kiss and perform other sexual acts on interrogators'.

Al-Hathloul, 31, once shared a stage with the then Meghan Markle at the One Young World Summit in Canada and was later jailed after filming herself behind the wheel of a car before a driving ban on women was lifted.

The report claimed that her interrogation had been overseen by Saud Al-Qahtani, a member of the crown prince's inner circle, who was accused of orchestrating the killing of the Jamal Khashoggi.

In echoes of the dismemberment of the dissident journalist at the Saudi consulate in Istanbul he was said to have told one of the women: 'I'll do whatever I like to you, and then I'll dissolve you and flush you down the toilet'.

Another woman activist claimed her interrogation sessions were overseen by the de facto Saudi ruler's younger brother, Khalid bin Salman.

The report said he would boast about his position of power, saying: "Do you know who I am? I am Prince Khalid bin Salman, I am the ambassador to the U.S., and I can do anything I like to you."

The prisoners were often transferred between Dhahban prison, near Jeddah, and an 'unofficial detention facility', according to the report. 

Baroness Kennedy said Saudi Arabia was in breach of numerous human rights agreements and treaties it had signed up to by its treatment of women whose charges included campaigning for a new political system in Saudi Arabia, talking to British journalists for a documentary and applying for a job at the UN.