LEGAL PRINCIPLE: CIVIL PROCEDURE — Locus Standi — Distinction from Estoppel
PRINCIPLE STATEMENT
Locus standi goes to the competence of the plaintiff to institute the action at all and affects capacity to sue, while estoppel is a defence that can only be established by evidence and assumes the action is properly before the court.
RATIO DECIDENDI (SOURCE)
Per Ogundare, JSC, quoting appellant's submission with approval, in Yesufu v. Gov. Edo State & Ors (2001) NLC-701996(SC) at pp. 8–9; Paras D–B.
"To argue that a person is estopped from making a claim in court there is a presumption that the action is properly before the court i.e., that the action is properly constituted in all respects. Estoppel is only a defence put forward by the defendant(s) in their pleadings in the case and can only be established by evidence. On the other hand the issue of locus standi goes to the competence or standing of the plaintiff to institute the action at all... consequently while estoppel is a rule of evidence, locus standi affects capacity to sue."
EXPLANATION / SCOPE
Locus standi and estoppel are distinct concepts. Locus standi affects the plaintiff’s capacity to sue and goes to the competence of the action. It can be raised at any stage, even by the court suo motu. Estoppel is a defence that assumes the action is properly constituted; it must be pleaded and proved by evidence. Locus standi is a threshold issue; estoppel is a substantive defence. Confusing the two leads to procedural errors. The court must determine standing before considering estoppel. The distinction ensures that only parties with sufficient interest can invoke the court’s jurisdiction. Estoppel does not confer standing where none exists.