The study, shared exclusively with The Independent, alleges that 309 political prisoners have suffered human rights abuses since Mohammed bin Salman became crown prince of the kingdom in 2017.
Grant Liberty, the human rights charity which conducted the report, says people have faced death for crimes carried out when they were as young as nine.
Researchers said 20 prisoners were arrested for political crimes they committed as children - with five of these inmates already put to death and an additional 13 currently facing the death penalty.
The sister of jailed Saudi women’s rights activist Loujain al-Hathloul - who is currently on her 23rd day of hunger strike - said she had been tortured and sexually abused in jail.
Lina al-Hathloul, Loujain’s younger sister, said: “My sister is an award-winning women’s rights activist, she has been nominated for the Nobel Prize and she is celebrated all around the world.
“Except at home in Saudi Arabia, where she languishes in a maximum-security prison. In prison, my sister has been tortured and degraded, and sexually abused. As long as women inside of Saudi Arabia cannot safely speak, it is the duty of the international community to raise its voice on their behalf.”
Loujain has been on hunger strike since 26 October in order to protest against the authorities’ refusal to give her regular contact with her relatives.
Human rights organisations say Loujain has been forced to endure abuse including electric shocks, flogging and sexual harassment while in jail. Loujain, who successfully campaigned to win Saudi women the right to drive, was arrested alongside 10 other women’s rights activists in Saudi Arabia in May 2018 – weeks before the country reversed the driving ban.
Loujain is awaiting trial on charges of communicating with foreign bodies hostile to Saudi, recruiting government employees to collect confidential information and delivering financial support to entities overseas who are hostile to the kingdom. Saudi officials have denied the torture allegations and said they were investigating claims of maltreatment.
Abdullah al-Ghamdi, a Saudi activist who lives in exile, said: “In 2012, I was granted asylum in Britain – I had been campaigning to put an end to the dictatorship and authoritarian policies in Saudi Arabia.
“I was lucky because I got out – but it is another story for my family. My mother, Aida Al-Ghamdi and two of my brothers were arrested. No explanation has ever been provided but there is no denying the truth. They were arrested not because they had committed a crime, but because of my activism. My mother is 64. She suffers from diabetes and high blood pressure.
“When she was arrested with my brother they were tortured in front of each other. They were beaten and had cigarettes put out on their skin. My brother was forced to record a video denouncing me so official Saudi channels could post it on social media. I was told that any contact with my family would endanger their lives further.”
Mr al-Ghamdi said he is still “forbidden from” speaking to his mother or brother - adding the lack of contact is agonising.
The study reports prolonged solitary confinement is widely utilised by the authorities, while prisoners are repeatedly blocked from consulting their legal teams.
Abdullah al-Odah, who is the son of Salman al-Odah, one of Saudi’s most prominent champions of political reform and human rights, said: “My father faces the death penalty in Saudi Arabia. His crime?
“He tweeted an innocuous message to his 14 million Twitter followers wishing an end to the diplomatic standoff with Qatar. They want to kill my father. If they do, it will be state-sanctioned murder.”
Lucy Rae, spokesperson for Grant Liberty, said: “This report details abuse on an industrial scale. Murder, torture, sexual assault – all of the worst human rights violations imaginable are here.
“The rest of the world needs to wake up – Saudi Arabia must not be welcomed into the community of respectable nations whilst it tortures, abuses and murders its own people."
The reports comes as Amnesty International calls for G20 leaders going to the virtual summit hosted by Saudi this weekend to “take the Saudi authorities to task for their shameless hypocrisy on women’s rights” - noting female empowerment is part of the kingdom’s G20 Agenda.
Amnesty is calling for G20 leaders to demand Loujain, Nassima al-Sada, Samar Badawi, Nouf Abdulaziz and Maya’a al-Zahrani, who were arrested in 2018 for their human rights work, are “immediately and unconditionally released”.
Lynn Maalouf, of Amnesty International, said: “For Saudi authorities the G20 Summit is critical: it is a moment for them to promote their reform agenda to the world, and show their country is open for business.
“Meanwhile, Saudi Arabia’s real reformers are behind bars. Instead of playing along with the Saudi government’s whitewashed narrative, G20 leaders should use this summit as an opportunity to stand up for the brave activists whose genuine commitment to women’s empowerment has cost them their freedom.
“This weekend Saudi authorities will talk up the reforms championed by imprisoned activists to garner business opportunities and political acclaim. The activists who continue to fight for human rights in Saudi Arabia are the true voices for reform, and they should be listened to, not locked up.”
Adam Coogle, a spokesperson for Human Rights Watch told The Independent, the G20 presidency has given Crown Prince Mohammad bin Salman’s government an “undeserved mark of international prestige”.
He added: "At a time when it has imposed the harshest and most sweeping period of repression of civil and political rights in modern Saudi history."
The Independent has contacted a representative of the Saudi government for comment.
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