POLICE INFORMER PRIVILEGE
R. v. Leipert,  1 S.C.R. 281
Per Lamer C.J. and La Forest, Sopinka, Gonthier, Cory, McLachlin,
Iacobucci and Major JJ.:
The rule of informer privilege is of such fundamental importance to the workings of a criminal justice system that it cannot be balanced against
other interests relating to the administration of justice. Once the privilege has been
established, neither the police nor the court possesses discretion to abridge it. The
privilege belongs to the Crown, which cannot waive it without the informer’s consent.
In that sense, the privilege also belongs to the informer. The privilege prevents not only disclosure of the informer’s name, but also of any information which might implicitly reveal his identity. In the case of an anonymous informer, it is almost impossible for a court to know what details may reveal his identity.
The informer privilege is subject only to the “innocence at stake” exception.
In order to raise this exception, there must be a basis on the evidence for concluding that disclosure of the informer’s identity is necessary to demonstrate the innocence of the accused. The accused’s right to full disclosure of documents in the Crown’s possessionin aid of the Charter guarantee of the right to make full answer and defence, as interpreted in Stinchcombe, has not created a new exception to the informer privilege rule. To the extent that rules and privileges stand in the way of an innocent person establishing his innocence, they must yield to the Charter guarantee of a fair trial. By permitting an exception where innocence is at stake, the common law rule of informer privilege does not offend this principle.
Where an accused seeks to establish that a search warrant was not supported
by reasonable grounds, he may be entitled to information which may reveal the identity of an informer notwithstanding informer privilege in circumstances where the
information is absolutely essential. “Essential” circumstances exist where the accused
establishes the “innocence at stake” exception to informer privilege. Thus, absent a basis
for concluding that disclosure of the information that may reveal the identity of the
informer is necessary to establish the innocence of the accused, the information remains privileged and cannot be produced, whether at the hearing into the reasonableness of the search or at the trial proper.
Anonymous tip sheets should not be edited with a view to disclosing them
to the defence unless the accused can bring himself within the innocence at stake
exception. To do so runs the risk that the court will deprive the informer of the privilege which belongs to him absolutely, subject only to the “innocence at stake” exception. It also undermines the efficacy of programs such as Crime Stoppers, which depend on guarantees of anonymity to those who volunteer information on crimes. In the case of an anonymous informer, where it is impossible to determine which details of the information provided by the informer will or will not result in that person’s identity
being revealed, none of those details should be disclosed, unless there is a basis to
conclude that the innocence at stake exception applies.
Here, the trial judge erred in editing the tip sheet and in ordering the edited
sheet disclosed to the accused. The identity of the anonymous informer was protected
by privilege and, given the anonymous nature of the tip, it was impossible to conclude
whether the disclosure of details remaining after editing might be sufficient to reveal the
identity of the informer to the accused. The informer’s privilege required nothing short of total confidentiality in this case. As it was not established that the informer’s identity
was necessary to establish the innocence of the accused, the privilege continued in place.
The trial judge also erred in declining to allow the Crown to delete the
reference to the informer from the material in support of the search warrant. Since the
accused has not brought himself within the “innocence at stake” exception, the trial
judge should have permitted the Crown to defend the warrant on the material in the
information to obtain the warrant with the reference to the Crime Stoppers’ tip deleted.