In the language of tabloid newspapers, Max Mosley's privacy suit against the News of the World has been sensational. It has provoked enormous public interest, both because of the lurid details of his sado-masochistic session with five prostitutes and because of his flamboyance, parentage and prominent position. Behind the headlines, though, there is a contest between two essential points of principle: an individual's expectation of privacy in the modern world and the importance of a free press in a civilised society. Mr Justice Eady has tipped the scales in favour of privacy over press freedom.

The court's chief finding in favour of Mr Mosley was a blunt reminder to all journalists that we stand and fall by the accuracy of our reporting. The News of the World - which is owned by News Corporation, the parent company of The Times - reported that Mr Mosley had indulged in a Nazi sex orgy. In fact, he had participated in a bondage session that involved prison guards and prisoners, lice inspections and vicious beatings and that was, in part, conducted in German. As Mr Eady noted, The News of the World misread the situation. Mr Eady concluded that Mr Mosley's sexual activities may have been “unconventional”, but he had not mocked the victims of the Holocaust. It may have been a mistake in good faith, but it was, nonetheless, a mistake. The judge's decision to find against the News of the World was reasonable. His refusal to award Mr Mosley exemplary damages was sensible.

But Mr Eady was quite wrong to claim that “there is nothing 'landmark' about this decision.” The finding has long-term consequences, both for English law and for British journalism.

His finding has redefined what is “reasonable” when it comes to a person's expectation of privacy. In essence, anyone involved in any kind of sexual activity conducted on private property involving any number of consenting adults (paid or unpaid) can expect privacy. This sounds healthy and liberal in theory, but, in practice, it is eccentric: if a man has sex with one prostitute, he may be able to be sure that she will be discreet, if he has sex with two, there is plainly a greater risk that the story will get out and if he has sex with five, then he may hope for privacy, but he can hardly expect it.

Mr Eady has effectively barred press coverage of sexual behaviour. This may well chime with public opinion, which understandably recoils at the intrusions of paparazzi photographers and the prurience of celebrity gossip-mongers. But Mr Eady's view that the public's “distaste or moral disapproval” does not justify any intrusion into the privacy of an individual moves the goalposts on the question of what is and what is not in the public interest. Some revile a moralising press. Others believe it is the duty of the press to take an ethical stand. Either way, it is a choice. The court has curbed this freedom of expression.

Nor is Mr Eady's claim that his finding will not inhibit serious investigative journalism reassuring. Newspapers were once deterred by stringent libel laws and excessive awards. Now privacy may prove the bigger hurdle in reporting complicated matters of public interest.

This was a poor case upon which to build support for privacy. Mr Mosley's predilections alienate many. His case encourages other wealthy people to try to suppress embarrassing information but does nothing to guard the privacy of those with less means to bring a lawsuit. This country has not brought in its own privacy law. The courts, though, are moving in that direction. Mr Eady has interpreted European law and imposed new boundaries between individual privacy and freedom of expression in Britain. That cannot be good for the press, Parliament or, ultimately, the public.