LEGAL PRINCIPLE: CRIMINAL LAW — Defences — Insanity — Standard of Proof
PRINCIPLE STATEMENT
The burden on the accused to prove insanity is on the balance of probability or preponderance of evidence, the same as in civil cases.
RATIO DECIDENDI (SOURCE)
Per Iguh, JSC, in Ani v. State (2002) NLC-3152001(SC) at p. 11; Paras B–C.
"This burden on the accused to prove his insanity, however, is merely as in civil cases, that is to say, on the balance of probability or the preponderance of evidence. See R. v. William Echem (1952) 14 WACA 158, R. v. Matthew Onakpoya (1959) SCNLR 384; (1959) 4 F.S.C. 150, Emeryl v. The State (1973) 6 S.C. 215 at 216."
EXPLANATION / SCOPE
The standard of proof for insanity is the balance of probabilities (civil standard). The accused need not prove insanity beyond reasonable doubt. The principle is well-established in Nigerian law. The accused must adduce sufficient evidence to tilt the scale. The standard applies to all criminal trials where insanity is pleaded. The court will evaluate the evidence and determine whether it is more likely than not that the accused was insane. The rule balances the presumption of sanity with the accused’s need to prove the defence. The prosecution may rebut with contrary evidence. The standard is the same for all affirmative defences.