"An inferior court falls into jurisdictional error if it mistakenly asserts or denies the existence of jurisdiction or if it misapprehends or disregards the nature or limits of its function or powers in a case where it correctly recognises that jurisdiction does exist. Such jurisdictional error can infect either a positive act or a refusal or failure to act. Since certiorari goes only to quash a decision or order, an inferior court will fall into jurisdictional error for the purposes of the writ where it makes an order or decision (including an order or decision to the effect that it lacks, or refuses to exercise, jurisdiction) which is based upon a mistaken assumption or denial of jurisdiction or a misconception or disregard of the nature or limits of jurisdiction.
Jurisdictional error is at its most obvious where the inferior court purports to act wholly or partly outside the general area of its jurisdiction in the sense of entertaining a matter or making a decision or order of a kind which wholly or partly lies outside the theoretical limits of its functions and powers. An inferior court would, for example, act wholly outside the general area of its jurisdiction in that sense if, having jurisdiction strictly limited to civil matters, it purported to hear and determine a criminal charge. Such a court would act partly outside the general area of its jurisdiction, if, in a matter coming within the categories of civil cases which it had authority to hear and determine, it purported to make an order of a kind which it lacked power to make, such as an order for specific performance of a contract when its remedial powers were strictly limited to awarding damages for breach. Less obviously, an inferior court can, while acting wholly within the general area of its jurisdiction, fall into jurisdictional error by doing something which it lacks authority to do. If, for example, it is an essential condition of the existence of jurisdiction with respect to a particular matter that a certain event or requirement has in fact occurred or been satisfied, as distinct from the inferior court's own conclusion that it has, there will be jurisdictional error if the court or tribunal purports to act in circumstances where that event has not in fact occurred or that requirement has not in fact been satisfied even though the matter is the kind of matter which the court has jurisdiction to entertain. Similarly, jurisdictional error will occur where an inferior court disregards or takes account of some matter in circumstances where the statute or other instrument establishing it and conferring its jurisdiction requires that that particular matter be taken into account or ignored as a pre-condition of the existence of any authority to make an order or decision in the circumstances of the particular case. Again, an inferior court will exceed its authority and fall into jurisdictional error if it misconstrues that statute or other instrument and thereby misconceives the nature of the function which it is performing or the extent of its powers in the circumstances of the particular case. In the last mentioned category of case, the line between jurisdictional error and mere error in the exercise of jurisdiction may be particularly difficult to discern.
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... the ordinary jurisdiction of a court of law encompasses authority to decide questions of law, as well as questions of fact, involved in matters which it has jurisdiction to determine. The identification of relevant issues, the formulation of relevant questions and the determination of what is and what is not relevant evidence are all routine steps in the discharge of that ordinary jurisdiction. Demonstrable mistake in the identification of such issues or the formulation of such questions will commonly involve error of law which may, if an appeal is available and is pursued, be corrected by an appellate court and, depending on the circumstances, found an order setting aside the order or decision of the inferior court. Such a mistake on the part of an inferior court entrusted with authority to identify, formulate and determine such issues and questions will not, however, ordinarily constitute jurisdictional error. Similarly, a failure by an inferior court to take into account some matter which it was, as a matter of law, required to take into account in determining a question within jurisdiction or reliance by such a court upon some irrelevant matter upon which it was, as a matter of law, not entitled to rely in determining such a question will not ordinarily involve jurisdictional error." (Citations omitted)