The high court has given a green light to a lawsuit against Saudi Arabia that has been brought by a prominent dissident living in London who has claimed he was the victim of a sophisticated hacking campaign by the kingdom.

Lawyers for Ghanem Almasarir, who is believed to live under police protection in the UK, said the decision to allow them to serve the claim against Saudi Arabia showed he had an “arguable” and legitimate case.

Martyn Day, of the firm Leigh Day, said: “This is a rare case brought in this country against the Kingdom of Saudi Arabia and we are pleased that the court has agreed that given the circumstances in this case, the targeting of an individual while he was living in the UK, they are prepared to enable us to serve the formal proceedings on the Saudi Government.”

The development comes days after the Guardian reported that Jeff Bezos, the owner of the Washington Post, may have been the victim of an alleged hack triggered after receiving a WhatsApp message that had apparently been sent from the personal account of the crown prince of Saudi Arabia.

According to an analysis of the billionaire’s mobile phone, the hack seems to have been connected to a malicious file sent to him by Mohammed bin Salman in May, 2018.

Saudi Arabia has said the revelations were “absurd”.

Both alleged hacking cases have been cited by independent experts who have pointed to the Saudis’ “pattern of targeted surveillance of perceived opponents” and people who are of “strategic importance” to the kingdom.

Agnes Callamard, the UN special rapporteur on extrajudicial killings, and David Kaye, the UN special rapporteur on freedom of expression, have called for an immediate investigation into the reported surveillance of Bezos by the US and other relevant authorities.

The White House on Thursday said it was “aware” of the reports about Bezos and was taking the situation “seriously”, but it also noted that Saudi Arabia was “obviously an important ally”.

When he was asked about the alleged hack, Steven Mnuchin, the US treasury secretary, said in an interview that American business leaders should “absolutely” continue to do business with Saudi Arabia, and that the kingdom’s relationship with the US in the defence and energy industries would not change due to “one article”.

Almasarir is a human rights activist and satirist who regularly pokes fun at the Saudi royal family and, in particular, the crown prince.

The 39-year-old shares his opinions through his YouTube channel, the Ghanem Show, which has had more than 300m views.

The satire is believed to have made him an enemy in the eyes of the Saudi government, which has been accused in the lawsuit of orchestrating a hack against two of Almasarir’s phones on 23 June 2018.

The alleged hacks occurred about two months after the alleged 1 May targeting of Bezos.

In a letter of claim to the Saudi embassy in May last year, his lawyers said: “A vast amount of Mr Almasarir’s private information was stored and communicated on his iPhones … This included information relating to his personal life, his family, his relationships, his health, his finances, and private matters relating to his work promoting human rights in Saudi Arabia.”

According to the letter, Almasarir’s phones were examined by independent experts at the University of Toronto’s Citizen Lab, which tracks the use of cyberweapons and allegedly confirmed that the satirist had been sent malicious texts that were “associated” with spyware.

Citizen Lab concluded with a “high degree of confidence” that Saudi Arabia was the ultimate party behind the hack.

The high court ruled that Almasarir’s lawyers could serve their claim form at the ministry of foreign affairs in Riyadh.

Almasarir has lived in London since 2003 and has said he has lived under police protection since 31 October 2018, just a few weeks after Khashoggi was murdered.

In a statement to the Guardian, Almasarir said: “For years it has seemed like the Saudi regime cannot be touched by the legal system but finally I have the opportunity to hold them to account in a fair and independent court of law and hopefully see justice served.

“I hope this latest development gives confidence to others who have been targeted in the same way by the regime that they can fight back.”

Almasarir has also described allegations of intimidation against him the Saudi government, including Twitter campaigns that are said to have promoted violence, and attempts to lure him back to Saudi Arabia.

The Saudi government did not immediately return a request for comment. It has previously not responded to questions about the lawsuit.