Privilege protects certain information from being revealed by a witness on the stand.
Solicitor Client PrivilegeEdit
Solicitor-client privilege is a class privilege and are presumed inadmissible.
This privilege is the "highest privilege recognized by the courts" which is "fundamental to the administration of justice" Violation of this privilege can "erode the public's confidence in fairness of the criminal justice system." As accused persons must have confidential access to advice to made properly informed decisions.
The privilege exists where a written or oral communication is :
- made in confidence or be of a confidential in nature;
- made to a professional legal advisor;
- for the purpose of giving and receiving legal advice.
This privilege applies not only between and a lawyer and their retained client, but can also apply between a Crown attorney and a police officer seeking legal advice.
Statements taken by an investigator on behalf of the defence is privileged and cannot be subject of disclosure to the crown.
The following have been considered privileged information:
- Emails between counsel and clients
- conversations between counsel and client in the courtroom even if caught on recording device.
- phone wiretap between counsel and client 
- identity of person paying legal fees
- lawyer bills and statement of accounts regarding clients
- R v McClure, 2001 SCC 14,  1 SCR 445
- Smith v Jones 1999 CanLII 674 (SCC),  1 SCR 455, at para 44 and 50
- Lavallee, Rackel & Heintz v Canada (AG) 2002 SCC 61 (CanLII),  3 SCR 209 at para 49
- R v Campbell, 1999 CanLII 676,  1 SCR 565 at para 49 [also referred to as R v Shirose] Solosky v. The Queen, 1979 CanLII 9 (SCC),  1 S.C.R. 821 at p. 835
- R. v. Caines, 2011 ABQB 660
- R. v. Peruta; R v Brouillette (1992) 78 CCC (3d) 350 1992 CanLII 3597 (QCCA)
- R. v. 1496956 Ontario Inc. (Stoneridge Inc.), 2009 CanLII 12328 (ON SC) at para 12
- R. v. Higham, 2007 CanLII 20103 (ON SC) at para. 21 to 22
- R. v. Martin, 2010 NBCA 41 (CanLII) at para. 64-65
- Kaiser (Re), 2012 ONCA 838 (CanLII) at para. 44 to 45
- Maranda v. Richer, 2003 SCC 67 (CanLII),  3 SCR 193 at paras 21-34
Exemptions from Solicitor-Client PrivilegeEdit
There are three occasions when solicitor‑client privilege may be overruled, namely when innocence at stake is engaged, the client's communications are themselves criminal, or it is necessary to protect public safety.
- Smith v. Jones, 1999 CanLII 674 (SCC),  1 S.C.R. 45
Innocence at StakeEdit
The threshold test for innocence at stake exemption from privilege was set out in R v McClure 2001 SCC 445 and summarized in R. v. Brown, 2002 SCC 32 as a two-step process. The accused must establish that:
- the information he seeks from the solicitor-client communication is not available from any other source; and
- he is otherwise unable to raise a reasonable doubt.
- If the threshold has been satisfied, the judge should proceed to the innocence at stake test, which has two stages.
- Stage #1: The accused seeking production of the solicitor-client communication has to demonstrate an evidentiary basis to conclude that a communication exists that could raise a reasonable doubt as to his guilt.
- Stage #2: If such an evidentiary basis exists, the trial judge should examine the communication to determine whether, in fact, it is likely to raise a reasonable doubt as to the guilt of the accused.
- It is important to distinguish that the burden in the second stage of the innocence at stake test (likely to raise a reasonable doubt) is stricter than that in the first stage (could raise a reasonable doubt).
- If the innocence at stake test is satisfied, the judge should order disclosure of the communications that are likely to raise a reasonable doubt, in accordance with the guiding principles discussed.
The purpose of litigation privilege is to create a "zone of privacy" around documents that were made in "relation to pending or apprehended litigation".
Litigation privilege protects documents that were should be created in the following circumstances:
- where the dominant purpose of the document is for existing, contemplated or anticipated litigation; and
- was created in answer to inquiries made by an agent for the party's solicitor; or
- was created at the request or suggestion of the party's solicitor; or
- was created for the purpose of giving them to counsel in order to obtain advice; or
- was created to enable counsel to prosecute or defence an action or prepare a brief.
- Blank v. Canada (Minister of Justice),  2 S.C.R. 319, at para. 34
- Kennedy v. McKenzie,  O.J. No 2060 (S.C.), 2005 CanLII 18295 (ON SC), per Ducharme J. at 20
The parties need the ability to have "full and frank discourse" in order for agreements to take place. Without protection these discussions may not take place.
The privilege protects the public interest in favouring settlement. It "promotes the interests of litigants generally by saving them the expense of trial". The disclosure of "without prejudice" communications has a tendancy to promote litigation.
The privilege applies where the following criteria are established:
- A litigious dispute must be in existence or within contemplation.
- The communication must be made with the express or implied intention that it would not be disclosed to the court in the event negotiations failed.
- The purpose of the communication must be to attempt to effect a settlement.
Where settlement fails the privilege is invoked and the communications cannot be used in the course of litigation. However, if settlement is successful, the communications may be used to prove the existence of a settlement contract.
The privilege is possessed by both parties to the litigation and cannot be unilaterally waived by one party.
The use of the term "without prejudice" alone is not determinative of whether settlement privilege applies.
- R. v. Pabani, 1994 CanLII 8723 (ON CA)
- Kelvin Energy Ltd. v. Lee 1992 CanLII 38 (SCC),  3 S.C.R. 235 at para. 48
- Pirie v. Wyld (1886), 11 O.R. 422,  O.J. No. 188 (QL) (Ont. H.C.), at para. 18 (“... letters written or communications made without prejudice, or offers made for the sake of buying peace, or to effect a compromise, are inadmissible in evidence. It seemingly being considered against public policy as having a tendency to promote litigation, and to prevent amicable settlements.”)
- Calgary (City) v. Costello, 1997 ABCA 281 (CanLII) at para. 60
John Sopinka, Sidney N. Lederman & Alan W. Bryant, The Law of Evidence in Canada, 3rd ed. (Markham: LexisNexis Canada Inc., 2009) at para. 14.322
- Hansraj v. Ao, 2002 ABQB 385 (CanLII) at para. 13
- Hansraj v Ao at para. 13
- Hansraj v Ao at para. 13
- TDL Group Ltd. v. Zabco Holdings Inc. et al., 2008 MBQB 86 (CanLII) at para. 30
Flegel Construction Ltd. v. Cambac Financial Projects Ltd., > 1983 CanLII 1019 (AB QB)
Communications regarding plea negotiations fall under the category of "public interest privilege" and so cannot be used in court. This includes negotiations regarding bail hearing as well as sentencing hearings.
This privilege exists to permit "frank and full discussions between counsel for the accused and counsel for the Crown." 
This kind of privilege cannot be waived by one party alone.
- R. v. Bernard,  A.J. No. 1007, 2002 ABQB 747 (CanLII) (Alta. Q.B.)
- R. v. Roberts,  A.J. No. 772 (Alta. Q.B.))
- R. v. Bernardo,  O.J. No. 1718, (Ont. Gen. Div.) at para 16
R. v. Delorme,  N.W.T.J. No. 51 (N.W.T. S.C.), 2005 NWTSC 34 at para 18
R. v. Roberts, supra, at para 60
R. v. Griffin,  A.J. No. 1455, 2009 ABQB 696 (CanLII) (Alta. Q.B.) at para. 65
- R. v. Bernard, supra, at para 39
R. v. Griffin, supra, at para 54
Informer privilege is intended to protect informants and "promote the giving of assistance to the police by citizens in the investigation and prevention of crime". It further encourages "other persons to provide assistance which would not likely otherwise be provided because of the extreme risks associated with disclosure of the identity of the source of the information." 
It is generally said that the prosecution does not need to disclose the identity of the police informer or provide information that may disclose the identity. This is especially the case in drug trafficking cases.
The court will only order the disclosure of the identity if it is needed to show the innocence of an accused person, known as the "innocence at stake" exception. This can apply where the informer is a material witness to the offence. The determination requires balancing of the relevance of the identity of the informer and the prejudice to the informer and public interest in law enforcement.
Courts have permitted defence counsel to ask a witness whether they have been an informer in the past and details about any history as an informer to support the theory that the witness invented the allegation of a drug rip off against the accused in expectation of receiving money.
- R. v. X and Y, 2012 BCSC 326 at at 18, 19
- R. v. Grey, 1996 CanLII 35 (ON C.A.)
- R. v. Scott 1990 CanLII 27 (S.C.C.), (1990), 61 C.C.C. (3d) 300 (S.C.C.)
- R. v. X and Y, 2012 BCSC 326 at 20
Bisaillon v. Keable, 1983 CanLII 26 (SCC),  2 S.C.R. 60
R. v. Leipert, 1997 CanLII 367 (SCC),  1 S.C.R. 281
Named Person v. Vancouver Sun, 2007 SCC 43 (CanLII)
R. v. Basi, 2009 SCC 52 (CanLII)
R. v. X and Y, 2012 BCSC 325
- R. v. Garofoli 1990 CanLII 52 (S.C.C.), (1990), 60 C.C.C. (3d) 161 at 193
- R. v. Toews et al 2005 BCSC 727
Public Interest Privilege and Investigative TechniquesEdit
The following have been recognized as privileged as an investigative technique:
- simulated ingestion of controlled substances
- location of a surveillance or observation post
- the location of tracking devices
- the location and methods of examining of secondary VINs 
- R. v. Mueckon, (1990), 57 C.C.C. (3d) 193 (B.C.C.A.)
- R. v. Lam 2000 BCCA 545 (CanLII), (2000), 148 C.C.C. (3d) 379 (B.C.C.A.)
R. v. Richards 1997 CanLII 3364 (ON CA), (1997), 115 C.C.C. (3d) 377 (Ont.C.A.)
- R. v. Guilbride,  B.C.J. No.1245 (Prov.Ct.)
- R. v. Boomer 2000 CanLII 4176 (NS SC), (2000), 182 N.S.R. (2d) 49 (S.C.)
R. v. Smith, 2009 ABPC 88 (CanLII)
- See also Canadian Criminal Evidence/Testimonial Evidence/Competence and Compellability#Spousal Immunity
Spousal privilege is a class protection of certain communications between husband and wife. It is a protection that is separate and apart from spousal competency.
A spouse who is found to be competent and compellable may still invoke privilege to protect their communications.
This class of privilege does not exist at common law, but rather was created by way of s. 4(3) of the Evidence Act, which states:
4 (3) No husband is compellable to disclose any communication made to him by his wife during their marriage, and no wife is compellable to disclose any communication made to her by her husband during their marriage.
Third parties may "testify to communications between husband and wife that were overheard, intercepted, or otherwise discovered".
A communication that does not fit into one of the class privileges may nonetheless be protected under the "case-by-case privilege" that can be applied to communications on an ad-hoc basis where the requisite criteria are met.
Case-by-case privilege can be invoked where:
- The communications must originate in a confidence that they will not be disclosed.
- This element of confidentiality must be essential to the full and satisfactory maintenance of the relation between the parties.
- The relation must be one which in the opinion of the community ought to be sedulously fostered.
- The injury that would inure to the relation by the disclosure of the communications must be greater than the benefit thereby gained for the correct disposal of litigation.
- R. v. Gruenke, 1991 CanLII 40 (SCC),  3 SCR 263
Where appropriate, "the courts will respect a promise of confidentiality given to a secret source by a journalist or an editor."However, where the public's interest in protecting sources is outweighed by other interests promises of secrecy cannot be maintained.
- the communication originates in a confidence that the identity of the informant will not be disclosed;
- the confidence is essential to the relationship in which the communication arises;
- the relationship is one which should be sedulously fostered in the public good; and
- the public interest in protecting the identity of the informant from disclosure outweighs the public interest in getting at the truth.
In R v National Post 2010 SCC 16, the Court found that the fourth criteria was not made out where a journalist would not reveal a source who had potentially forged documents implicating a former prime minister in a illegal transaction.
- R v National Post 2010 SCC 16
Waiver of PrivilegeEdit
Inadvertently disclosing privileged information does not automatically result in a waiver of privilege. Implied waiver could be established by knowledge of disclosure of the information and silence in response to disclosing the documents. The court must look at all the circumstances.
- R v Chapelstone Developments Inc. 2004 NBCA 96 (CanLII)
Only the client can waive solicitor-client privilege. It must be waived intentionally.
The client cannot be compelled to waive privilege by answering questions in the course of litigation. 
A waiver of privilege can arise from an accused making allegations attacking competency of counsel using what would otherwise be privileged information. The waiver of privilege only covers evidence concerning the issue alleged.