Actus reus & mens rea

CRL.01 — Actus Reus & Mens Rea

Core rule. Most offences require coincidence of a guilty act (actus reus) and a guilty mind (mens rea), proved beyond reasonable doubt. The Latin maxim: actus non facit reum nisi mens sit rea — the act alone is not criminal unless the mind is guilty.

Actus reus

The external element: conduct, circumstances, and (for result crimes) consequences. It must be voluntary — Bratty v AG NI [1963].

Omissions. No general duty to act. Liability for failing to act arises only where a duty exists:

• Statute (e.g. failing to provide a breath specimen)
• Contract — R v Pittwood (1902) (gatekeeper)
• Relationship — R v Gibbins & Proctor (1918) (parent/child)
• Voluntary assumption of care — R v Stone & Dobinson [1977]
• Creating a dangerous situation — R v Miller [1983]
• Public office — R v Dytham [1979]

Causation (result crimes): factual ("but for" — R v White [1910]) and legal. Legal cause must be more than minimal (R v Kimsey); defendant need not be the sole cause. Take your victim as you find them (thin-skull rule — R v Blaue [1975], includes beliefs). Breaks in the chain (novus actus): free, voluntary, informed third-party/victim acts, or events that are not reasonably foreseeable. Medical treatment rarely breaks the chain unless "palpably wrong" and independent (R v Cheshire [1991]; R v Jordan).

Mens rea

• Intention — direct (aim/purpose) or oblique: jury may find intent where the result was virtually certain and D appreciated this (R v Woollin [1999]; R v Nedrick). Oblique intent is evidential, not a definition.
• Recklessness — subjective: D foresaw a risk and unreasonably took it (R v Cunningham [1957]; R v G [2003], which overruled the objective Caldwell test).
• Negligence — objective failure to meet the reasonable standard (gross negligence manslaughter).

Traps and distinctions

• Coincidence: AR and MR must occur together, but courts treat a continuing act (Fagan v MPC [1969]) or one transaction (Thabo Meli v R [1954]) as concurrent.
• Transferred malice: MR transfers between like offences/victims (R v Latimer), not unlike ones (R v Pembliton).
• Strict liability: no MR for one or more AR elements (often regulatory); presumption of MR rebutted only by clear statutory intent (Sweet v Parsley [1970]; Gammon factors).
• Distinguish R v G (subjective) from the dead Caldwell objective test; don't confuse motive with intention.