Media correspondent, BBC News
When the News of the World splashed Max Mosley's picture on its front page, accusing him of taking part in a "sick Nazi orgy with five hookers", it seemed to have the Formula 1 boss bang to rights.
Mosley's win could impact on how stories are reported
If readers did not believe the story, they could watch the paper's secretly filmed video on its website and judge for themselves.
Mosley was hardly likely to sue for libel. The evidence seemed clear cut.
It was widely assumed that, like other public figures caught in such predicaments, he would hang his head in shame, apologise to his wife and family, and resign. Instead he fought back, claiming his behaviour was "a perfectly harmless activity, provided it is between consenting adults and... in private."
He sued the News of the World for breach of privacy, claiming punitive damages, and his success in the High Court means newspapers and broadcasters face a tougher battle to preserve the freedom of the press.
In the days when juries set libel payments, editors used to fear the prospect of a six-figure pay-out when tackling the rich and powerful. Now the law of privacy worries them more, even though Britain does not have a privacy law as such.
Instead we have "a privacy law by the back door" - a series of legal judgments that may or may not create precedents on which subsequent legal decisions can be based.
They are based on Article 8 of the European Convention on Human Rights.
Caroline Kean, head of litigation at the media law firm Wiggin, said: "The Human Rights Act introduced a statutory right to respect for one's private life, home and correspondence and a corresponding right to freedom of expression.
"Ever since, the courts have been struggling to find the balance between the two."
'Breach of confidence'
Recently the advantage has been shifting away from freedom of expression - and the Mosley judgment further tips the scales in favour of greater privacy.
The first significant test came in the Naomi Campbell case, which went back and forth, all the way to the House of Lords.
The Daily Mirror published a picture of the supermodel leaving a Narcotics Anonymous meeting. She claimed the publication had left her "shocked, angry and violated" and claimed damages, not for loss of privacy but on the more technical grounds of "breach of confidence".
Other famous celebrities have won similar cases
In the High Court, a judge awarded her damages of £3,500, even though he said she had lied about her drug abuse. The Appeal Court overturned that ruling, but the Law Lords backed the original judge - by a majority of three to two - saying there had been a "misuse of private information".
In another long running - and technically argued - case, Catherine Zeta-Jones and Michael Douglas won damages against Hello! magazine over spoiler pictures of their wedding.
The European Court of Human Rights found in favour of Princess Caroline of Monaco, saying paparazzi shots of the princess had infringed her privacy even in a public place.
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Spanking and bondage aren't my cup of tea, but I defend the right of consenting adults to do as they wish
Such cases still provide a field day for lawyers. There is always argument over the media's frequent defence that publication was "in the public interest", as claimed in the Mosley case.
And some judgments seem to have created a Catch 22 in the debate over whether to sue for privacy or defamation.
In the Campbell case, the Lords ruled that publication of the photo was an invasion of her privacy - but publishing details of her addiction was not. The newspaper said it had published the photograph to prove its story was true, as a defence against any libel claim. Yet by doing so, it laid itself open to a breach of privacy.
Similarly, in the Mosley case, the News of the World said it had secretly filmed the "orgy" to prove its story was true, once again laying itself open to a privacy claim.
The News of the World decided not to alert Max Mosley to the story in advance - and it was widely presumed that this would be held against it.
Mr Justice Eady said it was clear that one of the reasons for keeping the story "under wraps" was to avoid the possibility of an injunction.
However, he decided such tactics were not "deliberately or recklessly committing a wrong" and it would not be right to award "exemplary" damages to punish the paper, as Mr Mosley had asked for.
The News of the World's editor Colin Myler said he was pleased at that, but nonetheless concluded: "Our press is less free today after another judgement based on privacy laws emanating from Europe."