A group of British parliamentarians and lawyers urgently want to investigate allegations of torture, sexual harassment and threats of rape of detained female human rights defenders in Saudi Arabia, they said in a letter to the kingdom on Wednesday.
Over a dozen women's rights activists have been arrested since May, most of whom had campaigned for the right to drive and an end to the kingdom's male guardianship system, though some have since been freed.
The ban on women driving has since been removed, but the women arrested have remained in detention.
In November Amnesty International and Human Rights Watch accused Saudi Arabia of subjecting some of the female activists to torture and sexual harassment - allegations denied by a Saudi official to Reuters.
British parliamentarians and lawyers formed the group Detention Review Panel and submitted a letter to the Saudi ambassador to Britain requesting to investigate the allegations, and review the women's health conditions and rights.
"We hope to speak with the detainees and ascertain from them directly the manner in which they have been treated - that includes the physical and psychological treatment, and access to fair trial rights," said human rights lawyer Tayab Ali.
"Ultimately, we hope the detainees are released as soon as possible," he told the Thomson Reuters Foundation by phone from London.
A group of United Nations experts in October called for the immediate release of six female human rights defenders it said were still being held incommunicado in the kingdom.
In December sources told Reuters that one of the detained activists was subjected to kissing, groping and electrocution, and was threatened with rape.
The allegations come at a time when Saudi is facing an international outcry over the killing in October of Saudi journalist Jamal Khashoggi in the Saudi consulate in Istanbul.
"After Khashoggi, Saudi Arabia's reputation adhering to human rights and international standards of accountability are at an all time low," said Ali.
"This panel presents Saudi with the unique opportunity to regain some credibility with their intention in regards to their aim of reform, and their adherence to human rights."
Last June the Saudi government ended the decades-old ban on women driving cars as part of a bid to open up Saudis' cloistered lifestyles - and also lure investment from the outside world.
But while many hailed the end of the ban on women driving as proof of a new progressive trend, it has been accompanied by a crackdown on dissent.
The Detention Review Panel requested an "urgent response" from the Saudi ambassador by January 9. Saudi officials could not immediately be reached for comment.
