There is no doubt, however, that a court is expected in all proceedings before it to admit and act only on evidence which is admissible in law (i.e. under the Evidence Act or any other law or enactment relevant in any particular case) and so if the court should inadvertently admit inadmissible evidence it has a duty generally not to act upon it. When, however, inadmissible evidence is tendered it is the duty of the opposite (or adverse) party or his counsel to object immediately to the admissibility of such evidence; although if the opposite party should fail to raise objection in such circumstances the court in civil cases may (and, in criminal case, must) reject such evidence ex proprio motu. On appeal, however, different considerations arise where a party failed to take objection to inadmissible evidence in the court of trial. It has frequently been stated (as, indeed, learned counsel for the appellant has done) that where a matter has been improperly received in evidence in the court below, even when no objection has been there raised, it is the duty of the court of appeal to reject it and to decide the case on legal evidence.
— Ogundare, JSC. Kossen v Savannah Bank (1995) – SC.209/89