Pursuant to s. 12 of the Canada Evidence Act, a witness may be questioned as to whether he or she has been convicted of a criminal offence. Typically, the relevance of such evidence is in respect of the witness’s credibility, and the evidence cannot be used as bad character evidence or for propensity reasoning.
Under Corbett, a court can be asked to exclude parts of a criminal record where its probative value is outweighed by its prejudicial effect. The right to a fair trial is the context in which the balancing exercise must be effected. A jury is presumed to follow the court’s instructions about the proper use of evidence of prior convictions.
The question in each case is whether excision of the conviction in question would leave the jury with incomplete and therefore incorrect information about an accused’s credibility as a witness. Relevant factors include: the nature of the previous conviction; its remoteness or nearness to the present charge; and the similarity to the offence charged.
Another potential factor identified in Corbett is the need to maintain a balance between the position of the accused and that of a Crown witness who has been subjected to a credibility attack on the basis of his or her criminal record or otherwise, although this factor should not override the concern for a fair trial. Any attack on the integrity of a Crown witness is not sufficient to make the accused’s entire record admissible; rather, what is contemplated is an attack on the Crown witness’s credibility based on his or her character, especially as disclosed in his or her criminal record: R v McManus, 2017 ONCA 188 at paras 81-83
Where the defence points the finger of guilt at a third party, accompanied by a vigorous attack on the credibility of that person, to suggest he was the perpetrator, it would be unfair to prevent the use of the accused’s criminal record (with the most prejudicial parts having been excised) to assess his own credibility. However, where the defence calls its own witness with the intention that the jury accept his evidence that he, in fact, was responsible for the offence, the same concern does not arise: McManus at paras 89-92.
Standard of Review
Typically, deference is owed to a trial judge’s determination of a Corbett application, except where the decision is made on a wrong principle or where a trial judge fails to consider relevant factors in the exercise of his/her discretion. However, no deference is owed where the trial judge failed to give reasons: McManus at paras 84, 85.
Examples from the Case Law
In McManus, where the accused was charged with possession for the purpose of trafficking in marijuana and cocaine, the Court of Appeal held that the trial judge erred in ruling that the Crown could cross-examine him on his prior conviction for possession of cocaine for the purposes of trafficking. In weighing the prejudicial effect of the conviction, there was no question the balance favoured exclusion; the nature and timing of the conviction increased the risk of propensity reasoning by the jury. To properly assess his credibility, the jury could have been made aware of his other non-drug related convictions, without risking propensity reasoning. This error affected the fairness of M’s trial as he decided not to testify after the Corbett ruling: R v McManus, 2017 ONCA 188