What is the test for a superior court to order a writ of prohibition?

In considering this appeal it is important that there be kept in mind the principles upon which a superior court may exercise its power of supervision over an inferior court or tribunal As to prohibition, Lamont, J., in Segal v. Montreal (City) 1931 CanLII 82 (SCC), [1931] SCR 460, 56 CCC 114, affirming 46 Que KB 375, said at p. 471: “The principles governing the right to a writ of prohibition have been pretty well established, although in certain cases it is difficult to draw a sharp line between lack or excess of jurisdiction which gives the right, and the improper exercise of jurisdiction which gives no right. The first question which a judge has to ask himself, when he is invited to exercise a limited statutory jurisdiction, is whether the case falls within the defined ambit of the statute; if it does not, his duty is to refuse to make an order as judge; and, if he makes an order, he may be restrained by prohibition. Davey, L.J. in Farquharson v. Morgan [1894] 1 QB 552, 63 LJQB 474.”