Though estoppel is generally seen as a shield (defense),as it has been affirmed in various decided cases. It can also be used as a sword (a basis for a suit).
In Chinwendu v. Mbamali & anor (1980) 3-4 S.C. 31 at p.48 Aniagolu JSC said.
“It has been a long established practice in our Courts in this Court try for a defendant to plead a judgment given against a plaintiff where the plaintiff re-litigates the subject matter against him, but the practice is not often employed by a plaintiff against a defendant who raises issues already decided upon in a previous litigation.
Nothing however prevents a plaintiff from raising, in the original or further pleadings, estoppel against a defendant who makes assertions in his pleadings contrary to what had been solemnly declared in a previous judgment against him.”
The above decision was followed in the case of Odhevwedje v. Umurhurhuvwe (1987) NWLR (Pt. 52) 633. Here it was held thus:
“The defence of issue estoppel had been pronounced upon by this Court in quite a number of cases…
But one common feature of these cases is that generally it is always the defendant that raises the defence of issue estoppel against the plaintiff. The reverse hardly come by.
However it has since been settled that although the plea of estoppel is a shield for the protection of a defendant, it can also validly be employed as sword by a plaintiff…” (underlined for emphasis)
In Abalogu v. S.P.D.C. Ltd.  13 NWLR (Pt.837)309 it was held as follows:
“Although the plea of estoppel, generally, is a shield for the protection of a defendant, it has since been settled that… it can validly be employed as a sword by a plaintiff* but this, as above stated, must be confined to appropriate cases only.” Per Iguh, J.S.C. (P. 30, paras. D-F)”
See also Ukaegbu v. Ugoji (1991) 6 NWLR (Pt.196)127
RAJI v. OBAFEMI AWOLOWO UNIVERSITY (2014) LPELR-22088(CA) is also a case where estoppel was used as a sword.
The case in summary is that OAU appointed the appellant as a reader (associate professor) but on the condition that he will work for three years only as a probation after which they can retain or dismiss him base on his performance.
But after three years he continued working with OAU and OAU continued paying him his salary but after sometime OAU unilaterally disengaged the service of the Appellant on the ground that his appointment was not confirmed.
The Appellant raised an issue for determination inter alia:
“Whether the Appellant’s appointment was not confirmed by the Respondent after the 3 years probationary period since he was encouraged to keep on working and paid for his continuous service?”
The court held that by allowing the appellant to continue working after the probatory period and paying him during that probatory period is an implied confirmation of his appointment.
The case of the Appellant succeeded based on estoppel.
Furthermore, In OGUNDARE & ANOR v. EXECUTIVE GOVERNOR OF LAGOS STATE & ORS (2017) LPELR-41859(CA) it was held that:
“… it is also settled that the principle of promissory estoppel can be used as a sword depending on the peculiar facts of the case because it is a principle of justice and equity”
Lastly, In the recent case of ADAMS & ANOR v. FASASI & ORS (2018) LPELR-44379(CA) the Appellants use a previous court judgement as a sword (estoppel) and it succeeded.
The Court of Appeal held that:
“The plea of estoppel is generally employed as a shield for the protection of a defendant, but it can also be employed as a sword by a plaintiff in appropriate cases”
Article written by:
O. G. Chukkol is a student, Faculty of Law, ABU, Zaria.