A child's right to privacy as guaranteed in the European Convention on Human Rights, coupled with the ease with which the redacted information could be recovered by inexpensive software, meant that an injunction preventing the information being published should be imposed, the Court said.
The blacked-out information was contained in Greek court papers that determined how a father, Martin Coward, could have contact with his son and how his son would be educated, as well as details of the son's wealth.
Coward was fighting divorce proceedings with his wife Elena Ambrosiadou when he sent the redacted papers to the media. All the document contents could be read using software costing just £300, the court said.
"It is a powerful point in favour of granting an injunction particularly bearing in mind that ... access to all the information in the [Greek court judgment papers] has been provided by [Coward] to third party media organisations, ... much of the information appears to relate to the private and family life of a child, ... the fact that much of the information has not been published by the media, and ... it is quite possible that some media organisations have been holding off publishing in the light of the injunction granted," the Master of the Rolls said in the court ruling.
"It appears to me that there is considerable force in the [Ambrosiadou's] contention that, in the light of these factors, it would be appropriate for this court to reverse the decision of the Judge ... to refuse the injunction sought. After all, the risk of third parties publishing information contained in the redacted material is entirely due to [Coward's] unattractive behaviour in releasing many copies of the redacted [Greek court judgment papers] coupled with his ineptitude in failing to effect the redactions securely," the Master of the Rolls said.
"In my view, much of [the redacted document contains] information in respect of which [Ambrosiadou] and the boy had a reasonable expectation of privacy, and [the European Convention on Human Rights] is accordingly engaged," the Master of the Rolls said.
The ruling overturns a previous decision to withdraw the court order.
"It would seem that there would be nothing to prevent a person, to whom an ineptly redacted copy of the [Greek court judgment papers] was sent, actually reading the redacted material, and then publishing any information contained therein. An [interim] injunction restraining [Coward] from publishing such information would prevent such a person from doing so, provided that person had notice of the injunction, pursuant to the so-called Spycatcher principle," the Master of the Rolls said.
The Spycatcher principle binds anyone to a court order if they are aware of its terms. It refers to a gagging order placed on English newspapers who sought to report on a British spy tasked with finding a Soviet mole within the MI5.
During the Greek proceedings Coward had argued that his marriage with Ambrosiadou began to break down in 2008 when she dismissed his research and development staff at IKOS, the hedge fund management service company they had co-founded in 1992. Coward resigned as a director of IKOS in December 2009.
After the Greek court made its judgments about the son, Coward sent the papers and a copy of his resignation letter to a Daily Telegraph journalist. The journalist contacted Ambrosiadou whose lawyers made the paper agree not to publish a story before informing them. The Telegraph broke its promise when it published a story on 3 June 2010, although the "contents were not objectionable", the court said.
The following morning Ambrosiadou's lawyers threatened Coward with a court order.
"This prompted [Coward] to issue ...a statement ... just before midday. In that statement, he said that he had so far 'refrained from commenting in detail either to my former clients or to the media', but, following 'an open court hearing in Greece', he had decided to release a copy of the [Greek court judgment], which, as he explained, set out his resignation letter in full. As he also explained in the ... statement, the copy ... he was releasing had been redacted 'to protect the privacy both of IKOS clients and Dr Coward's son'," the court said.
Coward circulated copies of his statement and redacted versions of the Greek court judgment to more than 50 organisations, mostly media outlets.
"Unfortunately, the redacted version of the [Greek court judgment] could, with the use of a piece of non-standard, but fairly easily available, software costing around £300, be unredacted. In other words, the parts of the [Greek court judgment papers] which [Coward] had blanked out could be restored, and therefore read, by someone who had access to the necessary technical knowledge and the software," the court said.
Ambrosiadou's lawyers applied at short notice for a court ban on Coward communicating any of the couple's divorce proceeding papers, other than to his lawyers.
Mr Justice Maddison granted the ban without representation from Coward. Mr Justice Maddison issued the order with two provisions that said the ban did not "prevent or allow" Coward sharing information he held independently of the court papers, and that the ban would not apply if the papers become accessible to the public other than by a breach of the order.
The Daily Mail reported the story the following day on 5 June 2010 and "referred to the 'bitter divorce' between the parties, the defendant's allegations of the claimant's high-handed behaviour, and a custody battle," the court said.
Both parties were represented at a hearing in July 2010 when Mr Justice Eady ruled not to impose a ban. Mr Justice Eady did keep the original order in place until an appeal was heard.
The appeal court judges urged Coward and Ambrosiadou to agree the limitations of what the court order should ban, but said it would consider their arguments if the estranged couple could not agree.
There would be a ban on 'objectionable' content from the Greek court judgment papers being published, the court said.
"No reason has been advanced on behalf of [Coward] as to why it would be to his legitimate benefit to disseminate the [Greek court judgment papers] in any form, and, in the light of the unfortunate turn of events when he previously disseminated the notice, it appears to me that, in our discretion, we should preclude its further dissemination. It is not as if we would thereby [prevent] him from publishing any unobjectionable information in the notice," the Master of the Rolls said.