One exception to the general rule that relevant evidence should be admitted in a civil trial deals with prejudice. If the prejudicial effect of relevant evidence outweighs it’s probative value a trial judge has the discretion of excluding it. The BC Court of Appeal recently discussed this principle in the context of an ICBC claim.
In today’s case (Gray v. ICBC) the Plaintiff was involved in a motor vehicle collision. She was allegedly at fault for this crash and was sued by the driver and passenger in the other vehicle involved in the collision. The Plaintiff was insured with ICBC. ICBC denied coverage to the Plaintiff arguing that she was impaired at the time of the crash and therefore in breach of her insurance. The Plaintiff sued ICBC arguing she was not impaired and that ICBC was required to provide her coverage.
After the crash the Plaintiff was given a breathalyzer test by the Vancouver Police Department and her test yielded readings well above the legal limit. At trial the Plaintiff argued that the breathalyzer readings were faulty because the machine was not set up properly. ICBC responded with expert evidence stating that “there is nothing to indicate that the Breath Test Supervisor did not set up this instrument correctly“. The Plaintiff countered pointing out that there was nothing in the police files indicating what set up steps were taken by the Breathalyzer Supervisor. This left ICBC scrambling and in the course of trial they were able to locate the Breathalyzer Supervisor and the notes detailing the set up steps that were taken at the relevant time.
The Plaintiff objected to this evidence being introduced arguing that it’s late disclosure was severely prejudicial. The trial judge agreed. The Court held that while the supervisor could testify he could not rely on or refer to the breathalyzer maintenance notes in giving his evidence. Ultimately the Plaintiff succeeded at trial with the judge finding that she was not in breach of her insurance. ICBC appealed arguing the trial judge was wrong in excluding the evidence. The BC Court of Appeal allowed the appeal and ordered a new trial. In doing so the BC High Court provided the following reasons about the exclusion of prejudicial evidence:
As Mr. Justice Wood said, speaking for this Court in Anderson (Guardian ad litem) v. Erickson (1992), 71 B.C.L.R. (2d) 68 (C.A.), “There is no doubt that a Judge trying a civil case in Canada has a discretion to exclude relevant evidence on the ground that its prejudicial effect outweighs its probative value”…
 In my view, the trial judge erred in her approach to the exclusion of the documentary evidence prepared by Mr. Czech. In exercising her discretion, she was required to balance the probative value of the evidence against the potential prejudice to Ms. Gray of its admission and to make a judgment whether the prejudice outweighed the probative value. It is apparent that she did not undertake this exercise. Rather, she excluded the evidence after balancing the prejudice to the respondent, Ms. Gray, if the evidence were admitted against the prejudice to the appellants if it were excluded. Thus, she erred in principle in her approach and in failing to take into account a critically important factor – the probative value of the impugned evidence. It follows that she did not exercise her discretion judicially.
 Moreover, the trial judge erred in prohibiting Mr. Czech from using his records to refresh his memory. Witnesses are entitled to refresh their memory by any means, including by inadmissible evidence: see R. v. Fliss, 2002 SCC 16,  1 S.C.R. 535.
Interestingly the BC Court of Appeal did not determine whether the evidence should have been excluded, rather that the wrong test was used. The Court directed a new trial requiring the correct principle to be applied in deciding whether the evidence should be admitted.