The High Court in London granted the interim injunction to the "successful businessman" following a private hearing on 27 March after deeming that it was "justified and appropriate" to issue the non-disclosure and harassment order in the case.
The businessman, whose identity was anonymised by the court, was contacted by an unknown man who, the court said, has threatened to make public information that the businessman had had a sexual relationship with a woman, together with evidence of that relationship in the form of text messages.
The businessman had agreed to meet the alleged blackmailer on 28 March, the day after the hearing, which the woman and the alleged blackmailer were not notified of, where he intended to serve the interim injunction. The meeting had been arranged under the guise that a £75,000 payment would be made by the businessman to the alleged blackmailer.
Mr Justice Nicklin, the High Court judge, said though that if the meeting on 28 March did not take place, the businessman would be able to serve the interim injunction via text message.
"This is the latest case demonstrating that the court is willing to take a practical approach to the service of injunctions by alternative electronic means," said media law specialist Imogen Allen-Back of Pinsent Masons, the law firm behind Out-Law.com. "Previous judgments have permitted service via email and social media sites such as Twitter and Facebook."
According to the ruling, the court's order requires the woman who the businessman had an affair with and the unknown alleged blackmailer to state whether they have disclosed any communications between the woman and businessman to any other third party. In addition, the alleged blackmailer has been ordered to disclose his identity and address.
"Both are typical in cases like this where there is a justified concern about further dissemination of the private information and where the threat to publish is being made by someone who is hiding behind anonymity," Mr Justice Nicklin said.
In assessing the businessman's application for the interim injunction, the judge considered the likelihood of the businessman's claims for misuse of private information and/or harassment succeeding in a full trial. In this respect, he held the businessman was likely to establish that publication of the information about the affair should not be allowed.
Mr Justice Nicklin outlined his reasons for this in his judgment. He highlighted the need to consider the often competing interests of privacy and freedom of expression.
Specifically in relation to the misuse of private information claim, the judge said: "The information relates to a sexual relationship, and includes messages exchanged between the [businessman and woman he had an affair with]. The [businessman] is likely to establish that he has a reasonable expectation of privacy in this information."
"Although each case must be assessed on its own facts, the starting point is that there is not usually any public interest justification for disclosing purely private sexual encounters, even if they involve adultery. The blackmail element strengthens the claim. Such conduct considerably reduces the weight attached to be attached to any freedom of expression argument and correspondingly increases the weight of the arguments in favour of restraining publication," he said.
"In the ultimate balancing of the competing interests that might be advanced, the Article 8 [privacy] rights of the [businessman] are likely to prevail and a final injunction granted," the judge said.
Mr Justice Nicklin also said that he was satisfied that the businessman would be likely to show at a trial in the case that the acts of the alleged blackmailer in communicating their demands "is a course of conduct that amounts to harassment" and that it is "likely to be found that these demands are oppressive and unacceptable" for which the alleged blackmailer is unlikely to demonstrate a defence against.