- 1 Introduction
- 2 Calling Witnesses
- 3 Witnesses Refusing to Testify
- 4 Evidence by Commission
- 5 Topics
- 6 See Also
Testimonial evidence, also known as viva voce evidence or oral evidence, is evidence given by a witness in the form answers to posed questions.
When a competent witness has taken the stand, he "is required to answer all relevant questions put to him". There exist exceptions for questions invoking privileged information and certain self-incriminatory information. However, as a general rule, even incriminating questions must be answered.
The "involuntary participation of non-involved persons in litigation is a longstanding tradition of the legal system".
Every person "has a duty to testify to that which they have witnessed".
- R v Noel, 2002 SCC 67 (CanLII),  3 SCR 433 at para 25
- Section 5(1) of the Canada Evidence Act states "No witness shall be excused from answering any question on the ground that the answer to the question may tend to criminate him, or may tend to establish his liability to a civil proceeding at the instance of the Crown or of any person."
Northland Properties Ltd. v Equitable Trust Co., 1992 CanLII 2360 (BC SC), (1992), 10 C.P.C. (3d) 245 (B.C.S.C.) at 254-5) per Fraser J.
- D.W. Matheson & Son Contracting Ltd. v Canada (Attorney General), 2000 NSCA 44 (CanLII) per Cromwell J. at para 83
Purpose of Testimonial Evidence
Testimonial evidence is the best way to ensure the most reliable and credible evidence is available for the trier of fact to consider.
Witnesses are encouraged to be honest, accurate, and complete by requiring them to give evidence under the requirements that:
- the witness give an oath or affirmation to their evidence;
- their personal presence is necessary;
- they will be subject to cross examination
- R v Baldree 2012 ONCA 138 (CanLII) at para 44 appealed to SCC
The usual manner that a witness testify is by oral testimony in court (viva voce evidence) while the accused is present. (CCC s.650(1))
The witnesses' testimony must be relevant, material, and admissible. To see details on the scope of these requirements see Evidence.
Identifying witnesses and Using Pseudonyms
The Court has discretion to allow a witness to testify under a pseudonym only where a failure to do so would interfere with the administration of justice. This includes where the witness has reason to fear for their life.
- R v McKinnon, 1982 ABCA 302 (CanLII), (1982), 39 A.R. 283 (Alta. C.A.);
Attorney-General v Leveller Magazine Ltd,  1 All E.R. 745 (H.L.) (*no link)
R v McArthur, (1984) 13 CCC (3d) 152 (Ont. H.C.J.) (*no link)
- R v Gingras, 1992 CanLII 2826 (AB CA), (1992), 120 A.R. 300 (C.A.)
R v Mousseau, 2002 ABQB 210 (CanLII)
Impermissible Reasons for Calling Witnesses
The Crown may not call a witness whose evidence does not advance their case, but it merely for the purpose of cross-examining to show them not to be credible. Where such a witness is called, the judge should provided limiting instructions explaining that absence collusion, a jury cannot draw any adverse inferences against the accused due to the negative finding of credibility against the witness.
Communicating with Witnesses During Testimony
Counsel cannot talk to a witness between cross-examination and re-examination without asking for leave of the court. 
- R v Montgomery, 1998 CanLII 3014 (BC S.C.)
Exclusion of Witnesses
The judge has discretion to permit that a witness be recalled to be cross-examined further. This can include re-calling the accused to be cross-examined further. However, this discretion should be "exercised very cautiously".
R v RL, 2002 CanLII 49356 (ON CA) at para 6
Choice of Witnesses
Any party is entitled to call a witness who is competent to testify (See Competence and Compellability for details on competency of witnesses).
A party is also permitted call a witness that has already previously been called by the opposing party.
A party cannot call a witness for the sole purpose of discrediting a witness who has made a previous inconsistent statement.
The failure to call a witness can be used to make an adverse inference where there is no plausible reason not o do so and it is well within the power of the party to do so. However, where the evidence is merely cumulative or inferior en it should not be taken into account.
A failure to call a witness cannot be used to make a negative inference on credibility of the accused.
Crown Discretion to Call Witnesses
The Crown is under no obligation to subpeona or call witnesses for the benefit of the Defence. The defence are able to subpeona the witnesses themselves.
Failure of Accused to Testify
The failure of an accused to testify cannot be used to infer guilt. However, where the Crown sets out a case that "cries out for an explanation", the failure to testify fails to provide any basi to infer anything else but guilt.
R v Cook, (1960), 31 W.W.R. 148 (Alta. S.C.A.D.) (*no link)
R v Baiton, 2001 SKQB 264 (CanLII)
R v Sutton 2002 NBQB 49 (CanLII)
R v Soobrian 1994 CanLII 8739 (ONCA)
This relates mostly to crowns calling a witness apply under s. 9 CEA to cross examine (see Examinations#Cross-examining a party's own witness (Adverse or Hostile Witnesses)
- R v Lapensee, 2009 ONCA 646 (CanLII)
- See Credibility#Failure_to_Call_Witnesses
Roulette (K.T.), 2015 MBCA 9 (CanLII) at para 123
See also Role of the Crown
- R v Oddleifson (J.N.), 2010 MBCA 44 (CanLII)
Witnesses Refusing to Testify
Procedure where Witness Refuses to Testify
Witness refusing to be examined
545. (1) Where a person, being present at a preliminary inquiry and being required by the justice to give evidence,
- (a) refuses to be sworn,
- (b) having been sworn, refuses to answer the questions that are put to him,
- (c) fails to produce any writings that he is required to produce, or
- (d) refuses to sign his deposition,
without offering a reasonable excuse for his failure or refusal, the justice may adjourn the inquiry and may, by warrant in Form 20, commit the person to prison for a period not exceeding eight clear days or for the period during which the inquiry is adjourned, whichever is the lesser period.
(2) Where a person to whom subsection (1) applies is brought before the justice on the resumption of the adjourned inquiry and again refuses to do what is required of him, the justice may again adjourn the inquiry for a period not exceeding eight clear days and commit him to prison for the period of adjournment or any part thereof, and may adjourn the inquiry and commit the person to prison from time to time until the person consents to do what is required of him.
(3) Nothing in this section shall be deemed to prevent the justice from sending the case for trial on any other sufficient evidence taken by him.
R.S., c. C-34, s. 472.
Section 545 does not permit a justice to make an order of contempt against a witness who refuses to testify at a preliminary inquiry.
A witness charged with contempt of court for refusing to testify against gang members due to fear to safety can rely on the defence of duress. 
Evidence by Commission
- Competence and Compellability
- Refreshing Memory
- Testimonial Aids
- Testimonial Aids for Young, Disabled or Vulnerable Witnesses (Screens and Video-links)
- Long Distance Testimonial Aids
- Evidence by Commission