I believe that the true position in law is that where a ‘ document such as Exh. C is itself one which limits, extinguishes or transfers title, then if it turns out to be invalid or inadmissible for being an unregistered instrument the whole transaction is invalid. But where as in this case the document is a mere evidence of a transaction already completed, it can be good evidence of receipt of money but its invalidity or inadmissibility will not affect the validity of the transaction. It appears to me that the part of the transaction between the defendant and the Medusope family which took place before the execution of Exh. C, that is payment of purchase money and being let into possession, which was further evidenced by the defendants survey of the land and preparation of plan No. BPO 863 BUGXII on 28/3/78, were sufficient to transfer the title to her under customary law. See on this Isaac Talabi Ogunbambi v. Adeniji Soyonbo Abowaba (1951) 13 WACA 222: also Griffin v. Talabi (1948) 12 WACA 371.
— Nnaemeka-Agu, JSC. Adesanya v Otuewu (1993) – SC.217/1989