A British judge has ruled that a case against the kingdom of Saudi Arabia brought by a dissident satirist who was targeted with spyware can proceed, a decision that has been hailed as precedent-setting and one that could allow other hacking victims in Britain to sue foreign governments who order such attacks.

The case against Saudi Arabia was brought by Ghanem Almasarir, a prominent satirist granted asylum in the UK, who is a frequent critic of the Saudi royal family.

At the centre of the case are allegations that Saudi Arabia ordered the hacking of Almasarir’s phone, and that he was physically assaulted by agents of the kingdom in London in 2018.

The targeting and hacking of Almasarir’s phone by a network probably linked to Saudi Arabia was confirmed by researchers at the Citizen Lab at the University of Toronto, who are considered among the world’s leading experts in tracking digital surveillance of dissidents, journalists and other members of civil society.

Saudi Arabia is known to be a former client of NSO Group, whose powerful Pegasus hacking software covertly penetrates and compromises smartphones.

Almasarir praised the decision, emphasising the “profound effect” the kingdom’s alleged assault and spyware had had on his life.

“I no longer feel safe and I am constantly looking over my shoulder. I no longer feel able to speak up for the oppressed Saudi people, because I fear that any contact with people inside the kingdom could put them in danger. I look forward to presenting my full case to the court in the hope that I can finally hold the kingdom to account for the suffering I believe they have caused me,” he said.

Saudi Arabia’s attempt to have the case dismissed on the grounds that it had sovereign immunity protection under the State Immunity Act 1978 was dismissed by the high court judge.

The Guardian and other media outlets have reported on the Saudis’ extensive previous use of NSO’s Pegasus spyware in cases around the world, including researchers’ findings that the kingdom had targeted a close associate of the murdered journalist Jamal Khashoggi who was living in Canada, journalists for US and Qatari news outlets, and dissidents and human rights activists.

In the ruling, against which Saudi Arabia is likely to appeal, Justice Julian Knowles found that Almasarir’s case could proceed under an exception to the sovereign immunity law that applies to any act by a foreign state that causes personal injury. He also found that Almasarir had provided enough evidence to conclude, on the balance of probabilities, that Saudi Arabia was responsible for the alleged assault. Saudi Arabia’s claim that the case was too weak or speculative to proceed was dismissed.

Almasarir was represented by Ida Aduwa, associate solicitor at Leigh Day. “Today’s judgment sets a powerful precedent for other cases brought against foreign governments for the alleged use of spyware on individuals in the UK. I hope this judgment will serve as a beacon of hope to those individuals who have been targeted, that foreign governments cannot necessarily hide behind state immunity in these types of cases,” Aduwa said.

The decision could have profound implications for other individuals targeted or hacked by NSO’s spyware within the UK.

They include Lady Shackleton and Princess Haya, the former wife of Dubai’s ruler Sheikh Mohammed bin Rashid al-Maktoum. Both were hacked by the sheikh using NSO spyware during lengthy court proceedings between Haya and her former husband in London.

When Pegasus is successfully deployed against a target, it can silently infect any mobile phone, allowing the operator of the spyware to intercept calls and text messages, including those on encrypted apps, such as Signal or WhatsApp. It can track a mobile phone user’s location, and also control its camera and recorder, in effect turning the phone into a listening device.

The decision represented a validation of the research by Citizen Lab, which has provided evidence in similar cases in other courts, including in Haya’s case.

Citizen Lab’s senior legal adviser, Siena Anstis, said: “The high court’s dismissal of the KSA’s application is fantastic news for victims of digital transnational repression in the UK and represents an important first step along the way towards greater accountability. I also hope this decision serves as a wake-up call for the US or other jurisdictions where state immunity may still be used by authoritarian regimes to block these kinds of cases and leave spyware victims without judicial recourse.”

Saudi Arabia was represented by Antony White QC and Michelle Butler of Matrix Chambers. White and Butler did not immediately respond to the Guardian’s request for comment.

NSO has also not responded to a request for comment.