Public Interest Privilege. R v Cook
In R v Cook (Ont CA, 2014) the Court of Appeal took the oppourtunity to make the following salutory comments on the nature of 'public interest' privilege, which - if applicable - rendered some evidence inadmissible:
 I similarly conclude that public interest privilege does not apply. Public interest privilege involves a claim by a government or an official that certain information should be kept secret. Typical situations involve the need to keep police investigative techniques confidential or the protection and safety of individuals. The Crown has the burden of establishing the need to keep the identity of the author secret. The Crown attempted to satisfy this burden by alleging that the author’s mental health issues, fear of police and fear of retribution engage public interest privilege. However, there is no objective evidence underlying the author’s fears. On the record before us, the Crown’s burden has not been met.