The position, at least until any appeal by the BBC, is that a person under investigation, whether for historical sexual abuse or any other offence, has a "reasonable expectation of privacy" and cannot be identified unless that reasonable expectation is displaced.
The decision is likely to have a dramatic impact on the media but it should cause little concern in police circles. The police service has, at least since the Leveson Inquiry, generally supported the notion that a person under investigation should not be named until the point of charge (the point at which a Crown Prosecution Service lawyer decides that a person should be prosecuted because the evidence is such that a conviction is likely to succeed and that a prosecution is in the public interest). The College of Policing issued guidance (prompted by a letter from Theresa May during her time as Home Secretary) that suspects should only be named if there is a legitimate policing purpose for their identification, for example where there is an immediate risk to the public. South Yorkshire Police did not willingly collaborate with the BBC to name Sir Cliff Richard for a legitimate policing purpose. On the contrary, it seems that the police only cooperated with the BBC because they feared that the BBC would otherwise publish information that would undermine a planned operation.
The Sir Cliff Richard judgment now prevents the media from identifying a person under investigation for purely journalistic reasons but it does not prevent the police from naming a suspected person for operational reasons. Whilst the practice of "shaking the tree" (naming a person under investigation to encourage victims or witnesses to come forward) has been criticised for attracting time-wasters and fantasists, Mr Justice Mann does not suggest that it is not a valid operational reason for identifying a suspect to the media. If the police pass on a name for an operational reason, the "reasonable expectation of privacy" is displaced and the media can lawfully publish it. The judgment therefore fundamentally changes the balance of power between the police and media and has, in the words of Fran Unsworth, the BBC's Director of News "put decision-making in the hands of the police".