Private Prosecutions. R v McHale
In R v McHale (Ont CA, 2010) the Court of Appeal usefully sets out the procedures for the launching of a private prosecution and two appeal grounds relating to private prosecutions. In doing so the case reviews the common law and the statutory (Criminal Code) law extensively. Practically all of the case [paras 4-12,31-88] is a must-read for anyone involved with a private prosecution.
. R v Olumide
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. . Lochner v. Ontario (Attorney General)
 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 Lochner v. Ontario (Attorney General) (Ont CA, 2019) the Court of Appeal considered an unusual appeal regarding a related series of private prosecutions below. The case is interesting for the private prosecution procedures gone through [paras 5-18].