LEGAL PRINCIPLE: CRIMINAL LAW – Applicable Law for Trial – Law in Force at Time of Offence
PRINCIPLE STATEMENT
The applicable law for criminal trials is the law in force at the time the offense was committed; subsequent amendments that come into force after the offense cannot apply retrospectively unless expressly stated.
RATIO DECIDENDI (SOURCE)
"The law is well settled that the applicable law is the law in force at the time the offence was committed... The Criminal Code (Amendment No.1) Law 1980 of Lagos State which came into force on the 29/9/80 not being retrospective cannot be the applicable law as on 2nd April 1980."
EXPLANATION / SCOPE
This principle establishes the fundamental rule against retrospective application of criminal law amendments, flowing from the constitutional principle of legality (nullum crimen sine lege—no crime without law). The law in force when the offense was committed defines: (1) what conduct is criminal; (2) the elements of the offense; (3) available defenses; (4) sentencing provisions; (5) procedural requirements. Subsequent amendments changing any of these cannot apply to earlier conduct unless the legislature explicitly provides for retrospective application. This rule serves critical purposes: (1) Fair notice—persons must know at the time of acting whether their conduct is criminal and what penalties apply. Retrospective criminalization violates this notice requirement. (2) Legal certainty—people plan their affairs based on existing law and should not face criminal liability based on laws enacted after their conduct. (3) Protection from arbitrary prosecution—preventing prosecutors from using favorable subsequent amendments to secure convictions for conduct that wasn’t criminal when committed. (4) Constitutional protection—most constitutions prohibit retrospective criminal laws except those favorable to the accused. In this case, an amendment taking effect September 29, 1980 could not apply to an offense committed April 2, 1980. The intervening months make clear the conduct preceded the amendment. Courts must determine: (1) the date the offense was committed; (2) the law in force on that date; (3) whether any subsequent amendments purport to apply retrospectively; (4) if so, whether retrospectivity is constitutionally permissible (generally only if more favorable to the accused). The principle has a corollary: amendments more favorable to accused persons (reducing penalties, creating new defenses, decriminalizing conduct) may apply retrospectively even to pending prosecutions, as this advances justice without violating fair notice. The principle ensures criminal liability is determined by the legal landscape as it existed when conduct occurred