R. v. Desjardin, 2019 ABCA 215 - SummaryR v Desjardin, 2019 ABCA 215 (CanLII)
What should the prosecution do when an inadvertent mistake by their lawyer precludes an accused from raising a Charter argument, though the prosecution received advanced notice of this argument? Not argue against allowing the accused to correct the mistake and raise the Charter argument by saying it is "too late", that is for certain.
It is, however, the position that the prosecution took in this file at trial. The defence had mistakenly admitted as an exhibit a piece of evidence it wanted to have excluded on Charter grounds. The prosecution tried to hold that error against the accused. On appeal, it rightfully changed its position to concede that when an honest mistake occurs which prevents an accused from raising a Charter argument, a new trial should be ordered. The Court of Appeal of Alberta commends the prosecution for this change of position, reiterating the role of Minister of justice played by the Crown in criminal trials [par. 11].
But that is on appeal. What should be done when the mistake is discovered during the trial, with the prosecution adequately agreeing that a remedy should be found to allow the trial to continue fairly? The Court gives some guidance: "any issues requiring further questioning could have been addressed by recalling that witness, or by declaring a mistrial and restarting the trial afresh before the same trial judge." [par. 9]