My noble lords, nobody is disputing or denying the operation of the general principle of proof in civil matters by casting the burden of proof on the plaintiff where the averments contained in the statement of claim were traversed by the defendant. In such a situation, the defendant will have to wait for the plaintiff to lead evidence in proof of his averments. This is understandable. It is also elementary. It accords with common sense as he who invokes the aid of the law should be the first to prove his case. But, where the situation presents a little difficulty is in a statement of defence where the defendant introduces a new issue which transforms his line of defence by transforming him now into an asserter of a fact which requires evidence to be led first in order to discharge the burden now cast on him and in order not to allow the suit to stagnate. By way of example: A sues for money due on a bond. The execution of the bond is admitted, but says that it was obtained by fraud, which A denies. If no evidence were given on either side, A would succeed as the bond is not disputed and the fraud is not proved. Therefore, the burden of proof is on B, although a defendant. It was who introduced fraud. It was his duty to prove it in order to succeed. It is only by settling the issue of fraud, firstly, in one way or the other that a meaningful progress can be made by the court of trial towards the completion of the entire trial.
— Muhammad JSC. Nnaemeka Okoye & Ors. v. Ogugua Nwankwo (SC. 234/2004, 27 Jun 2014)