men don‟t bite,” he noted. Similarly, in Atuanya v. Onyejekwe (1975) NSCC 88, the landowner merely told the improver that his vendor had no authority to sell the family land without more. The improver stubbornly continued building. The trial judge held that the warning was inadequate. This judgment was upheld by the Supreme Court without assenting or dissenting from this observation. Proprietary Estoppel: Shield or Sword The current attitude of the Supreme Court is that proprietary estoppel cannot be used as a sword but as a shield – it cannot be used as a cause of action by the improver as plaintiff, but can be used as a defence when he is sued. This proposition may not be entirely correct. Although promissory estoppel cannot be used as a sword, but who says that proprietary estoppel should not? The person who, mistakenly, believing he has a right to land, incurs expenditure on the land while the true owner stands by without enlightening him acquires an enforceable equity which entitles him to certain rights over the land. It follows that he must be allowed to sue to establish these rights. In Atuanya v. Onyejekwe supra, Ibekwe JSC pontificated: “Acquiescence in law has the effect of extinguishing the plaintiff’s title and in the case of ejectment, of neutralizing the plaintiff’s claim. We think that it is not possible for the court to decree title in the plaintiffs (landowners) and at the same time uphold the plea of acquiescence put forward by the defendant (improver). One must give way for the other in as much as acquiescence, once made out, tends to annihilate or defeat the plaintiff’s claim to title.” In effect, if acquiescence (proprietary estoppel in this context) extinguishes the landowner‟s title, it must necessarily reside in the person who