In the case of National Insurance Corporation of Nigeria Ltd. v. Power and Industrial Engineering Co. Ltd. (1986) 1 NWLR (Pt. 14) 1 at 29, Aniagolu, JSC had this to say: “Equity, as we all know, inclines itself to conscience reason and good faith and implies, system of law disposed to a just regulation of mutual rights and duties of men, in a civilized society. It does not envisage sharp practice and undue advantage of a situation and a refusal to honour reciprocal liability arising therefrom; it will demand that a person will enter into a deal as a package-enjoying the benefits thereof and enduring, at the same time, the liabilities thereon.”
Though not mutually executed Exhibit A was regarded by the parties as their binding contract. Equity acts in personam and therefore takes as done that which ought to be done, if from the conduct of the parties such inference can be drawn. In the instant case, such facts abound on which the two Courts below concurrently found that the parties intended to be bound by Exhibit A and that Exhibit A would be the basis of their mutual transaction, whether or not the document was formally executed. Again, Equity acting in personam would look at the intent of the parties and the substance and not at the form. In the instant case, insistence on compliance with all formalities of executing a written agreement will be oppressive to the Respondent. The Appellant, in the Court of Justice, will not be allowed to take advantage of the Respondent on his own iniquity by his ingenious booby trap by which he deliberately withheld his signature while at the same time it made the Respondent go with the impression that the relationship is governed or regulated by Exhibit A. Section 169 of the Evidence Act, 2011, which codified the principle of estoppel by conduct, will not countenance the present posture of the Appellant and allow it resile out of Exhibit A.
— E. Eko, JSC. MTN v. Corporate (2019) – SC.674/2014