Criminal Law
Criminal Law
Criminal Law tests whether conduct satisfies the definition of an offence, whether a defence applies, and how far liability extends to attempts and accomplices. The exam rewards element-by-element analysis: actus reus, mens rea, concurrence, causation, and defences.
Core rules
- Legality: No crime without a pre-existing, clear legal basis; ambiguous penal provisions are construed narrowly.
- Actus reus: A voluntary act or a breach of a recognized duty to act. Status alone is not conduct; omission liability requires a legal duty (statute, contract, assumption, or creation of risk).
- Mens rea: Intention, knowledge, recklessness, or negligence as the definition requires. Motive is not an element.
- Concurrence and causation: The mental element must accompany the prohibited conduct; factual and legal causation must link conduct to result.
- Defences: Self-defence requires an imminent unlawful attack and a proportionate response; necessity requires imminent peril and no reasonable alternative; duress overbears the will. Insanity tests vary but usually require a defect affecting understanding or control.
- Inchoate and complicity: Attempt requires intent to commit the complete offence plus a substantial step; accomplices are liable if they intentionally assist or encourage, sometimes with knowledge of the principal’s purpose.
Worked example
D sees V raising a knife and advances. D punches V, causing a broken jaw. V had been joking and the knife was plastic. Self-defence is assessed on the facts as D reasonably believed them, but the belief must be honest and, in most tests, reasonable. If D’s mistake was unreasonable, proportionate-force self-defence may fail; if the jurisdiction requires only honest belief, D may be acquitted. The key is to separate the objective attack from D’s subjective perception and then test proportionality.
Traps
Do not convict on bad motive alone. Do not impose omission liability without identifying a duty. Do not mix attempt with completed offence mens rea. In complicity, do not equate mere presence with assistance. Check whether a defence is complete or partial, such as reducing murder to manslaughter.