To establish locus standi for a declaratory order under section 14 of the High Court Act, an applicant must be an 'interested person' with a direct and substantial interest in the subject matter that could be prejudicially affected by the court's judgment. The interest must concern an existing, future, or contingent right. For final interdictory relief, an applicant must establish: (i) a clear or definite right; (ii) an injury actually committed or reasonably apprehended; and (iii) the absence of a suitable alternative remedy. A general assertion of illegality, without demonstrating how one's own rights are infringed, is insufficient to ground either declaratory or interdictory relief. To establish that a local authority acted ultra vires statutory provisions, an applicant must identify specific statutory sections violated and provide evidence that lawful procedures were not followed.