HRH Prince of Wales v Associated Newspapers Ltd [2006] EWCA Civ 1776, [2006] All ER (D) 335 (Dec):
The test to be applied when considering whether it is necessary to restrict freedom of expression to prevent disclosure of information received in confidence is not simply whether the information is a matter of public interest but whether, in all the circumstances—including the nature of the information—it is legitimate for the owner of the information to seek to keep it confidential or whether it is in the public interest that the information should be made public.