Canadian Criminal Procedure and Practice/Pre-Trial Matters/Mandamus, Certiorari, and Prohibition

General Principles of Mandamus
An order of mandamus is a common law "prerogative writ" power of a superior court to order a lower court or government agent to perform a mandatory duty correctly. It is a discretionary remedy to compel a lower court to exercise jurisdiction where it has incorrectly refused to do so.

A prerogative writ is a manner of correcting errors of jurisdiction made by inferior courts as well as correcting failures of natural justice or procedural fairness.

When the duty is of a judicial nature, mandamus is not available regardless of whether the decision was incorrect. No superior court can change that decision except for exceptional circumstances such as prejudice, bias, personal interest, dishonesty, and the like.

The order is only available where the body refuses to exercise its jurisdiction.

Despite having jurisdiction, a superior court can refuse prerogative relief if there is an equally effective alternative remedy.

General Principles 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.

It is not sufficient that there be an error on a Charter issue, statutory interpretation, admissibility of evidence, or sufficiency of evidence.

It is for this reason that the reviewing court's job is different from that of a court on a straight appeal.

A successful application of certiorari will quash the reviewed decision of the lower court.

Case Digests

 * R. v. Coughlan (1969), [1970] 3 C.C.C. 61 (Alta. T.D.) - applicant sought to compel a magistrate to issue a summons or warrant who refused to do so after a hearing. The reviewing judge refused to order the writ as it was a discretionary decision of the magistrate.
 * R. v. Faber, (1987), 38 C.C.C. (3d) 49 (Que. Sup. Ct.) - applicant sought to compel the attorney general to withdraw a stay of proceedings against someone charged with murder