The U.K. Supreme Court upheld an injunction banning News Corp.’s Sun on Sunday newspaper from revealing details about a celebrity’s sex life, delivering a blow to publishers seeking a sales boost from reporting on the affair.

The married star at the center of the story, whose identity can’t be revealed because of the court order, had a number of sexual encounters, including a threesome with a couple who tried to sell the story to the press. His identity was published in the U.S. and Canada and other nations.

“There is no public interest, however much it might be of interest to the public, in publishing kiss-and-tell stories,” Supreme Court judge Jonathan Mance said Thursday. The court upheld the injunction, even though details are widely available online, until a trial can be held, saying the story breached the privacy of the star and his family.

A spokeswoman for News Corp.’s U.K. business declined to immediately comment.

The latest spat between celebrities and Britain’s tabloid press comes at a difficult time for the newspaper industry. Print sales have been falling for years and publishers are struggling to profit from online journalism. Meanwhile, illegal phone-hacking by News Corp.’s News of the World and other papers led to a backlash against media intrusion, lawsuits, criminal prosecutions and a public inquiry.

‘Swing Back’

“The judgment today is clearly a major swing back in favor of granting greater privacy protection,” said Gideon Benaim, a lawyer who specializes in reputation protection and who isn’t involved in the case. “Spurious claims that something is in the public interest, when it clearly isn’t anything of the sort, have suffered a major blow.”

The case of PJS, as judges called the anonymous star, shows the U.K.’s famously abrasive tabloids still relish a fight, especially when it comes to the money they can make from the sex lives of the rich and famous.

“Circulations and site traffic are still driven by scoops,” said Alex De Groote, a media analyst at Peel Hunt who covers several British publishing groups including Trinity Mirror Plc and Daily Mail and General Trust Plc. “In the Twitter age, newspapers cannot afford to be constrained by injunctions if they want to remain relevant commercially.”

Tabloid Start

It was Victorian newspaper editor William Thomas Stead who pioneered the combination of moral outrage and prurience that’s still found on London newsstands 130 years later. When he ‘bought’ a 13-year-old prostitute and printed a series of articles in the Pall Mall Gazette, the paper quickly sold out and copies were traded for 20-times their original value. Stead was later imprisoned for abduction.

Stead’s critics called him a pornographer. His supporters said he was carrying out a public service in exposing injustice.

The modern version of that debate puts laws protecting an individual’s right to privacy in conflict with the public’s interest in freedom of speech. The argument has proved especially fraught in the U.K., with its aggressive press and strict laws.

“A lot of privacy law - and newspaper regulation in general - was dreamt up in a bygone age,” De Groote said.

State Secrets

In 2011, Manchester United soccer star Ryan Giggs won a so-called “super-injunction” barring reporting of his affair with a reality television star or any discussion of the court order. The injunction was lifted in 2012 after a lawmaker, John Hemming, said his name in Parliament, where speech is protected, enabling the press to publish it.

“I am sad that the Supreme Court have decided that the fact that someone has had a threesome is a state secret where ordinary people gossiping about it could be sent to prison,” said Hemming, who is no longer an MP. “This state secrecy undermines society, allowing the rich and powerful to conceal things that they find embarrassing simply by throwing money at the legal industry.”

PJS asked for a court injunction stopping the Sun on Sunday’s story because he said it would harm the couple’s young children. What made the dispute unusual was that media outlets in the U.S., Canada and Scotland published details about the case because they weren’t bound by the English court. That meant anyone searching online could identify PJS, and left the Sun on Sunday fighting for a scoop that was already available elsewhere.

Unresolved Issues

“The wider question of privacy protection in an online world remains unresolved,” said Amber Melville-Brown, a reputation lawyer at Withers.

It’s hard to say how much extra revenue the PJS story itself would have provided for News Corp.’s publications, according to Ian Whittaker, a media analyst at Liberum Capital Ltd. In the long-term, “if you establish a reputation for scoops, people buy your paper even if they are not your target demographic,” he said. “This sort of case is almost like brand marketing.”