In relation to the administration of justice, there are two broad classifications of law. In they are; Substantive law and procedural law.
The branch of law that defines,prescribe,imposes and/or confers right,duties and obligation is called substantive law. In other words the substantive law include; constitutional law,criminal law,law of tort,law of contract etc.
Adjectival law on the other hand is that branch of la w that regulates the application and enforcement of substantive law,and the manner of presentation of fact before a court of law. The law of evidence is a branch of adjectival law and other branch is of law of procedure. See Broadband vs. Olayiwola (2015) 3 NWLR(pt691) 622at 653; Ukaego vs. Ugorji (1996)6 NWLR(pt196)127at 155; Avong vs.K.R.P.C. Ltd(2002)4NWLR(pt758)this8at 530; N.V.Sheep vs. M. V "S.Araz" (2002)15 NWLR (pt 691)622 at 653.
Substantive law are inextricably linked and cannot be separated from the other. For instance the constitution 1999 as amended confrlers the set of fundamental right in chapter iv thereof. However the constitution does not prescribe the procedure by which an applicant who alleges violation of his right can seek judicial redress.
The procedure for enforcement of fundamental right is set in the fundamental right (enforcement procedure) rule 2009. In this example of substantive law, the fundamental right (enforcement procedure) rule is an example of adjectival law. In filing an application for the enforcement of fundamental right,an applicant must satisfy the provisions of the evidence Act relating to affidavit evidence. Hence the evidence Act is also an example of adjectival law. "See s. 107-120 evidence Act dealing with affidavit."
Similarly while the criminal code (criminal code cap 37laws of Rivers state of Nigeria 1999 or criminal code cap 37 LFN 2004). While the criminal code prohibit certain conduct which are criminalised the administration of criminal justice Act(federal law) 2006 or the administration of criminal justice (state law)2006 prescribe the procedure of the criminal code. The law of evidence as a branch of adjectival law consists of rules which prescribe and define what fact are admissible or admissible in evidence and manner in which such fact can presented before the court of law. Therefore it is submitted that the thrust of the law of evidence as stated by the supreme court in Ukaego vs. Ugorji supra is that it pre scribe admissible and inadmissible evidence.
According to Sir James Stephen the law evidence deals essentially with three broad matters namely;
1. It defines what fact may or may not be admitted in a Judicial proceding
2. It defines the kind of evidence that may g given in prove of fact.
3. It defines the person by whom and the manner in which admissible evidence may be presented before the court.
See James Stephen - a digest of the law of evidence 6th edition 1904 ix. See also Avong vs.K.R.P.C. Ltd supra at p. 530.
It follows from the ongoing that the primary concern of the law of evidence is the presentation of fact in Judicial or quasi Judicial proceedings. In prescribing the manner of presentation of evidence, the law of evidence seeks to achieve fairness in the judicial process. See Olale vs. Ekwelendu (1989)4 NWLR(pt155)326at 360-361. Where it was held that the whole essence of judicial adjudication is to ascertain the truth between the contending parties and the law of evidence prescribe a reliable procedure by which the court can search for the truth.