Criminal Law

Actus Reus — The physical element of a crime: a voluntary act, an omission (where there is a duty to act), or a state of affairs. The act must be voluntary (R v Larsonneur [1933] remains controversial).

Mens Rea — The mental element: intention (direct or oblique, as in R v Woollin [1999]), recklessness (R v Cunningham [1957] for subjective recklessness), negligence, or strict liability (no mens rea required).

Coincidence of Actus Reus and Mens Rea — Both elements must coincide in time, though the courts apply the 'continuing act' theory (Fagan v Metropolitan Police Commissioner [1969]) or 'transaction' principle to ensure justice.

Causation — The defendant's act must be both the factual cause ('but for' test) and the legal cause (operating and substantial cause) of the prohibited consequence. Intervening acts may break the chain of causation (R v Smith [1959]).

Murder — Unlawful killing with intention to kill or cause GBH (R v Vickers [1957]). The mandatory sentence is life imprisonment.

Manslaughter — Voluntary manslaughter (loss of control under s.54 Coroners and Justice Act 2009, or diminished responsibility under s.52) and involuntary manslaughter (unlawful act manslaughter or gross negligence manslaughter — R v Adomako [1995]).

Defences — Self-defence (s.76 Criminal Justice and Immigration Act 2008), duress (R v Hasan [2005]), intoxication (R v Majewski [1977] — distinguishing specific and basic intent), insanity (M'Naghten Rules [1843]), and automatism.

Inchoate Offences — Attempt (Criminal Attempts Act 1981), conspiracy (Criminal Law Act 1977), and encouraging or assisting crime (Serious Crime Act 2007).