Rule 65, Sec. 1, Rules of Court
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When any tribunal, board or officer exercising judicial or quasi-judicial functions
has acted without or in excess of its or his jurisdiction, or with grave abuse of
discretion amounting to lack or excess of jurisdiction, and there is no appeal, nor
any plain, speedy, and adequate remedy in the ordinary course of law
An independent suit based ont he specific groudns specified therein. Generally, not allowed as a substitute for the lost remedy of an ordinary appeal (which includes certiorari 45)