Private Prosecutions - Crown Stay. P.C. v. Ontario (Attorney General)
In P.C. v. Ontario (Attorney General) (Ont CA, 2020) the Court of Appeal considered a Crown stay of prosecution:
 The appellant also challenges the application judge's failure to quash the stay entered by the Crown on the charge on which the justice decided to issue process.. R v Olumide
 Section 579(1) of the Criminal Code authorizes the Attorney General or counsel instructed by the Attorney General for that purpose, at any time after any proceedings have been commenced and before judgment, to direct entry of a stay of proceedings. The stay entered in this case after the pre-enquete justice had decided to issue process on one count was timely: McHale, at paras. 85-86.
 Entry of a stay of proceedings under s. 579(1) of the Criminal Code is a core element of prosecutorial discretion. Exercise of that discretionary authority is reviewable only in cases of “flagrant impropriety": Krieger v. Law Society of Alberta, 2002 SCC 65,  S.C.R. at paras. 46, 49.
 The appellant’s final allegation of error arises out of a comment the application judge made during the hearing and repeated in the final paragraph of her written reasons. In essence, she questioned whether the grievance of the appellant's partner which formed the basis of the offences alleged was not more properly addressed in the labour relations and civil context than by the institution of criminal proceedings.
 In our view, this observation on the part of the application judge was well warranted in the circumstances. After all, what set this entire train of events in motion was an unfavourable performance review. There followed a rapid escalation from these job performance beginnings to invocation of the blunt instrument of the criminal law.
 The observation of the application judge is also consistent with the purposes of the pre-enquete. Among those purposes are to ensure that spurious allegations, vexatious claims, and frivolous complaints barren of evidentiary support do not carry forward into a prosecution and to guard against the initiation of criminal proceedings to further claims that belong in another forum: McHale, at paras. 65, 74.
In R v Olumide (Ont CA, 2014) the Court of Appeal reiterated the criteria for setting aside a Crown stay of a private criminal prosecution:
 Section 579 of the Criminal Code gives the Attorney General the authority to direct a stay of proceedings at any time. The discretion to do so is reviewable only in the event of abuse of process. There is a presumption of prosecutorial good faith: see Krieger v. Law Society (Alberta) 2002 SCC 65 (CanLII) and R. v. Nixon 2011 SCC 34 (CanLII). The appellant has the onus of proving an abuse of process in the exercise of prosecutorial discretion. . R. v. Glegg
 Mr. Olumide alleged that the Attorney General is in an inherent conflict of interest and this constitutes an abuse of process. The motion judge found that there was no evidence of abuse of process. Absent proof of an abuse, the discretion is not subject to review by the court: Campbell v. Ontario (A.G.) (1987), 1987 CanLII 4333 (ON CA), 35 C.C.C. (3d) 480 (Ont. C.A.), leave to appeal refused,  S.C.C.A. No. 202. There is no evidence to point to an abuse of process.
In R. v. Glegg (Ont CA, 2021) the Court of Appeal considers an appeal from a Crown stay of a private prosecution. Private prosecutions are quite rare and interesting, so I harvest them when I can. This is a longish one written by Watt JA, so if you're involved with a private prosecution it's worth a review.