By Jon Silverman
Although the OK! versus Hello! battle has been bracketed with other landmark cases concerning the developing law of privacy, it is, strictly speaking, about commercial confidentiality.
Catherine Zeta Jones and Michael Douglas married in New York
What the Law Lords were asked to decide was this: Did Hello magazine breach commercially confidential information in publishing unauthorised photos of the wedding of Michael Douglas and Catherine Zeta Jones?
By a majority of three-to-two, they decided that it had.
Delivering the lead opinion, Lord Hoffmann said that OK! had paid more than a £1m for an exclusive contract to publish authorised photos of the wedding and that imposed an "obligation of confidence" which covered all photos of the wedding.
Lord Hoffmann did not believe the ruling created an "image right", which would be a novel concept in English law. But the effect may come close to that.
Publicist Max Clifford said: "This establishes the principle that celebrities can sell the exclusive rights to their wedding or other event, safe in the knowledge that they no longer need to spend a fortune on security or surveillance in case someone slips in with a hidden camera.
"This will make a big difference to enforcing exclusive deals."
If this is the impact of the judgment, it may be interpreted as bringing the UK closer to some other jurisdictions, notably France, where the law is used to prevent the unauthorised publication of photographs or other private information about celebrities.
Two of the five Law Lords were clearly troubled by this possibility.
In a dissenting judgment, Lord Walker disagreed with the view that English law enabled a celebrity to claim a monopoly in his or her image "as though they were a trademark or brand".
He added: "I think this goes some way towards creating an unorthodox and exorbitant form of intellectual property."
And Lord Nicholl rejected OK!'s claim to commercial confidentiality because its authorised photos were little different from the unauthorised ones published by Hello!.
The law lords took the view that OK!'s claim to compensation fell because there was no evidence that Hello! had deliberately set out to cause economic harm to its competitor.
And it looks as though the huge costs of this long-running battle may be shared between the parties.
But the core legal argument on commercial confidentiality appears to have been settled as far as the domestic courts are concerned.
The general issue of privacy, though, is such a fast-expanding area of law that it will almost certainly be tested again before too long.