It is trite law in Nigeria on the authorities I have earlier cited in this judgment that the defence of estoppel, whether founded on admissions or not, must be pleaded and, if it has not been pleaded, any evidence tending to establish it goes to no issue and the evidence ought to be rejected: Ogboda v. Adulugha (1971) 1 All N.L.R. 86. This is a general statement of the law. Let us see if the High Court of Lagos (Civil Procedure) Rules, 1972, which is the applicable law, make provision for an exception.
— M. Bello, JSC. Salawu Ajide V. Kadiri Kelani (SC.76/1984, 29 Nov 1985)