Nnaemeka-Agu, JSC, in ATANDA V. AJANI (1989) 3 NWLR (Pt. 111) 511 @ 546 put that point across most forcefully when he said that: “It appears to me that the rule which required every fact upon which a party intends to rely at the hearing to be pleaded goes to the fundamentals ofjustice. For no one can defend the unknown. If one has to defend or counter a fact made by his adversary, the one must have due notice ofthat fact to enable him prepare for his defence. That is the very essence of pleading. As it goes to the very root of the rule of audi alteram partem one of the twin pillars of justice — it would be a misconception to describe it as mere technicality or irregularity. It is a matter which cannot, therefore, be waived. Indeed, by a long line of decided cases, it has been long settled that any evidence on a fact that ought to have been pleaded, but is not, goes to no issue at all at the trial and ought to be disregarded.”
COURTS ARE BOUND TO DECIDE CASES ON THE PLEADINGS
The foregoing is the gist of the simple case presented before the trial judge. But it was made very complicated by the introduction of legal technicalities at the hearing of the appeal in this Court. The matter was further compounded by the conduct of the parties in that neither, as was disclosed by the issues canvassed before us, had any respect for the truth. However, courts are bound to decide cases on the pleadings of the parties and admissible evidence.
— M. Bello, JSC. Salawu Ajide V. Kadiri Kelani (SC.76/1984, 29 Nov 1985)