Writ of Certiorari
Certiorari is type of common law writ where the applicant seeks judicial review of a judge's decision by a higher court. It can only be issued when the reviewable court has exceeded its jurisdiction or otherwise a breach of the rules of natural justice, fraud, or an error of law so fundamental a character that it constitutes a defect amounting to a failure or excess of jurisdiction.
Unlike an appeal, an application for certiorari can be brought at any point in a proceeding, and is not limited to the conclusion of the proceeding.
The right to certiorari is discretionary arising out of the inherent jurisdiction of the superior court. The right can be denied on the basis of "unnecessary delay" or lack of "good faith".
- Third-party Right of Review
The scope of available review is more expansive when the petitioner is a third-party to the criminal proceedings.
For example, third-parties may apply for certiorari on pure errors of law.
- Effect of Successful Application
A successful application of certiorari will quash the decision of the lower court.
- Standard of Review
The reviewing judge must afford "greatest deference" to the lower court it is reviewing.
Patterson v The Queen, 1970 CanLII 180 (SCC),  SCR 409, 2 CCC (2d) 227, per Judson J, citing Lord Sumner in R v Nat Bell Liquors, Ltd. (1922), 47 CCC 129 (P.C.), 1922 CanLII 488 (UK JCPC):
- That the superior Court should be bound by the record is inherent in the nature of the case. Its jurisdiction is to see that the inferior Court has not exceeded its own, and for that very reason it is bound not to interfere in what has been done within that jurisdiction, for in so doing it would itself, in turn, transgress the limits within which its own jurisdiction of supervision, not of review, is confined. That supervision goes to two points: one is the area of the inferior jurisdiction and the qualifications and conditions of its exercise; the other is the observance of the law in the course of its exercise.
- Re Madden, et al. v The Queen, 1977 CanLII 2081 (ON SC), 35 CCC (2d) 381 (Ont. H.C.J.), per Henry J
R v Faulkner, 2013 ONSC 1824 (CanLII), per Code J, at para 5
R v Papadopoulos, 2005 CanLII 8662 (ON CA), 201 CCC (3d) 363, per curiam, at para 20
- R v Awashish, 2018 SCC 45 (CanLII), per Rowe J (9:0), at para 12
Awashish, ibid., at para 12
R v Stipo, 2019 ONCA 3 (CanLII), per Watt JA (3:0), at para 50
- R v Brown, 2012 ONSC 6565 (CanLII), per Fuerst J
R v Eckstein, 2012 MBCA 96 (CanLII), 293 CCC (3d) 292, per Chartier JA, at para 9
R v Catellier, 2016 MBQB 190 (CanLII), per McKelvey J, at para 3
R v Karpenko, 2005 MBQB 40 (CanLII), per Beard J, at para 11
Limitations on Review of Certiorari
Review by certiorari is "very limited". It is primarily a "jurisdictional review" or surveillance of statutory tribunals.  The reviewing court cannot overturn a decision based merely on error in law or a decision "different from that which the reviewing court would reach." The court may only intervene where "the tribunal has acted in excess of its assigned statutory jurisdiction or has acted in breach of the principles of natural justice".
The mere fact that the reviewing judge may have concluded differently does not entitle the court to intervene.
Erroneous ruling on evidence is not a failure of jurisdiction and so cannot be reviewed on certiorari.
- Errors of Law
Generally, errors of law are not reviewable by certiorari.
It is not sufficient that there be an error on a Charter issue, statutory interpretation, admissibility, or sufficient of evidence. 
- Statutory Right of Appeal
Certiorari should generally be denied when the inferior court's enabling statute provides a right of appeal or where there is an adequate alternative remedy. 
It is only in very rare cases that expediency would be a reason to grant a writ where there is a statutory right of appeal. Even where an appeal of a forfeiture order requires separate appeals to different levels of court, they should still be denied a writ to consolidate.
- When Not Available by Statute
By function of s. 776, no writs of certiorari are available where an appeal ins undertaken, or where an appeal was available but was not taken.
- No Horizontal Review
A superior court has no jurisdiction to review a decision of another superior court judge.
- R v Russell, 2001 SCC 53 (CanLII),  2 SCR 804, per McLachlin CJ, at para 19
- R v Deschamplain, 2004 SCC 76 (CanLII), per Major J, at para 37
- R v Beaven, 2012 SKCA 59 (CanLII), per Lane JA
Deschamplain, ibid., at para 17
Russell, supra, at para 19 ("The scope of review on certiorari is very limited. ... Thus, review on certiorari does not permit a reviewing court to overturn a decision of the statutory tribunal merely because that tribunal committed an error of law or reached a conclusion different from that which the reviewing court would have reached. Rather certiorari permits review “only where it is alleged that the tribunal has acted in excess of its assigned statutory jurisdiction or has acted in breach of the principles of natural justice which, by the authorities, is taken to be an excess of jurisdiction”: ")
R v MacDonald, 2007 NSSC 255 (CanLII), per Murphy J
- R v Faulkner, 2013 ONSC 1824 (CanLII), per Code J, at paras 4, 6
- R v Smith, 2018 ONSC 1614 (CanLII), per Schreck J, at para 16("in my view only in very rare cases would mere convenience or expediency be a sufficient reason for this court to grant prerogative relief in a situation where Parliament has created a right of appeal, particularly where that appeal is to a higher court.")
Dagenais v CBC, 1994 CanLII 39 (SCC),  3 SCR 835, per Lamer CJ,, at p. 865 ("...certoriari does not lie against a decision of a superior court judge.")
A reviewing court's job is different from that of a court on a straight appeal. The role is only to review the exercise of jurisdiction. 
Any failure on the part of the judge to "observe mandatory provisions of the Criminal Code" will result in a loss of jurisdiction.
Deciding an issue reserved only for a different forum is also jurisdictional error.
There is a difference between errors of law and errors of jurisdiction. The distinction is on the process followed by the judge.
A failure to consider all evidence or a consideration of an irrelevant consideration may amount to an error in jurisdiction. 
- R v Innocente, 2004 NSCA 18 (CanLII), per Hamilton JA ("The role of the reviewing judge on an application for certiorari is thus substantially different from that of a judge on appeal. It is only when the judge whose decision is being reviewed has acted in excess of his or her jurisdiction or has breached the principles of natural justice that certiorari will be granted.")
- R v Patterson, 1970 CanLII 180 (SCC),  SCR 409, per Judson J
Dubois v The Queen, 1986 CanLII 60 (SCC),  1 SCR 366, per Estey J
R v Whynot, 1994 CanLII 4130 (NSCA), , (1994) 129 NSR (2d) 347, per Chipman JA, at para 13 citing Dubois: ("In applying the wrong test for sufficiency, a preliminary inquiry judge does not commit jurisdictional error. In deciding an issue reserved to another forum, however, he does.")
- R v Duncan, 2004 CanLII 45468 (ON SC), per Trafford J, at para 19
R v Lee, 2014 ONSC 2471 (CanLII), per MacDonnell J, at para 9
R v Deschamplain, 2004 SCC 76 (CanLII), per Major J, at para 18
The following have been found to be jurisdictional errors:
- a preliminary inquiry judge committing an accused to stand trial where there is no evidence on an essential element of the offence charged
- a preliminary inquiry judge committing an accused to stand trial based on inferences that cannot be reasonably drawn.
e.g. Cohen c. Quebec (Attorney General), 2012 QCCS 4715 (CanLII), per Zigman J
R v Firth, 1987 CanLII 3546 (AB QB), per Cavanagh J
- e.g. Brown, supra
- R v Ellis, 2012 NSSC 329 (CanLII), per Pickup J
R v Sazant, 2004 SCC 77 (CanLII), per Major J
R v Deschamplain, 2004 SCC 76 (CanLII), per Major J
R v Brown, 2012 ONSC 6565 (CanLII), per Fuerst J, at para 21
R v Sheardown, 2010 ONSC 4235 (CanLII), per T Ducharme J, at para 21 ("To commit an accused on such a basis constitutes jurisdictional error as there is no evidence from which the inference or inferences reasonably can be drawn and thus, there would be an absence of evidence on an essential element of the charge.")
Attacking search warrants by way of prerogative writ is generally not frequently used nor considered effective since nullifying a warrant will not necessarily make the evidence inadmissible at trial without establishing its exclusion under s. 24(2).
A subpoena may be quashed if the "party seeking to uphold a subpoena is not able to demonstrate that the witness would “likely” or “probably” have material evidence then certiorari may issue to quash the subpoenas".
Committal at Preliminary Inquiry
- See also Preliminary Inquiry
In the context of a preliminary inquiry, it is within the inquiry judge's jurisdiction to draw inferences of fact in their decision of commit. However, if the judge "preferred an inference favourable to an accused to an inference, also availed on the evidence, favourable to the Crown."
A failure to make the correct decision on the evidence may not necessarily result in a loss of jurisdiction. There must be an absence of even a "scintilla of evidence" supporting an essential element of the charge.
It will be an error of jurisdiction where the preliminary judge "failed to test the evidence adduced at the inquiry against the essential elements of the offence". This also requires that the elements considered must be the correct ones.
The consideration of irrelevant factors in committal may result in a loss of jurisdiction.
Skogman v The Queen, 1984 CanLII 22 (SCC),  2 SCR 93, per Estey J, at p. 167
R v Kamermans, 2016 ONCA 117 (CanLII), per curiam, at para 13
Surette v Prince, 1999 CanLII 1929 (NS SC), per Richard J
Kamermans, supra, at para 15
R v Sazant, 2004 SCC 77 (CanLII),  3 SCR 635, per Major J, at para 25
R v Nichols, 2005 CanLII 26602 (ON SC), per Durno J, at paras 38 to 40 citing Skogman, at p. 173
Kamermans, supra, at para 14
Sazant, supra, at para 25
Kamermans, supra, at para 14
Sazant, ibid., at para 28
R v Dubois, 1986 CanLII 60 (SCC),  1 SCR 366, (1986) 25 CCC (3d) 221 (SCC), per Estey J