"The Crown's right of appeal from an acquittal of an indictable offence is limited to 'any ground of appeal that involves a question of law alone'. The jurisprudence currently recognizes at least four types of cases in which alleged mishandling of the evidence may constitute an error of law alone giving rise to a Crown appeal of an acquittal; this may not be an exhaustive list. First, it is an error of law to make a finding of fact for which there is no evidence. However, a conclusion that the trier of fact has a reasonable doubt is not a finding of fact for the purposes of this rule. Second, the legal effect of findings of fact or of undisputed facts may raise a question of law. Third, an assessment of the evidence based on a wrong legal principle is an error of law. Fourth, the trial judge's failure to consider all of the evidence in relation to the ultimate issue of guilt or innocence is an error of law, but this error will be found to have been committed only if the reasons demonstrate that this was not done. The trial judge's reasonable doubt did not have to be based on the evidence; it could arise from the absence of evidence or a simple failure of the evidence to persuade him to the requisite level of beyond reasonable doubt. It is only where that reasonable doubt is tainted by a legal error that appellate intervention in an acquittal is permitted."
