Parties and witnesses involved in litigation talk to each other. It is hard to prevent this from happening. This can have an effect on the evidence that the parties and witnesses subsequently give. How the court deals with the evidence of parties and witnesses where there is possible collusion or tainting can be a difficult issue. 

A recent criminal law Court of Appeal decision, R. v C.G., 2021 ONCA 809 (CanLII). contains a great discussion of various sorts of “collusion” and “tainting”, and how a trial judge is to deal with this evidence. 

Briefly, the facts of R. v. C.G.. involved an allegation of sexual assault. The complainant gave evidence of the assault in the accused’s home. The accused, his wife and daughter gave exculpatory evidence. The trial judge, in his reasons, said that collusion was a factor in assessing the defence evidence. 

In the appeal decision, the Court of Appeal distinguished between “advertent” collusion and “inadvertent” collusion. Advertent collusion occurs where witnesses get together and fashion their evidence in concert in order to appear to be reciting a consistent and reliable story. “Inadvertent” collusion occurs where one witness discusses the events with another witness with the consequence that the evidence of one or both of them may be altered. Hearing the evidence of the other witness “can have the effect, whether consciously or unconsciously, of colouring and tailoring their descriptions of the impugned events.” 

The mere presence of a possibility of inadvertent collusion does not render the evidence unreliable. If inadvertent collusion is possibly present, the trial judge must go on to consider whether the alleged inadvertent collusion affected the evidence of the witness, and to what extent.  

The Court of Appeal was also critical of the term “inadvertent collusion”.  The presence the word “collusion” suggests a conspiracy, which is a credibility concern. The Court suggested that a better term would be “inadvertent tainting”. 

Although the R. v. C.G. decision was in a criminal context, the discussion of collusion or tainting can also apply to civil matters as well, where collusion or tainting may also apply to the evidence of witnesses. 

Thanks for reading. 

Paul Trudelle