Actus Reus: The Guilty Act
The actus reus is the external element of a crime — the physical act (or omission) that constitutes the offence. It must be a voluntary act; involuntary conduct (such as a reflex action, an act during sleep, or an act under physical compulsion) does not satisfy the actus reus requirement (Hill v Baxter [1958] 1 QB 277).
The actus reus may consist of: (1) a positive act (e.g., striking someone), (2) a state of affairs or circumstances (e.g., being in possession of a controlled substance), or (3) a consequence (e.g., death in murder).
Liability for Omissions
English criminal law generally imposes no duty to act — there is no "Good Samaritan" law. However, criminal liability for an omission arises where the defendant was under a legal duty to act. Recognised duty situations include:
Statutory duty: e.g., failure to provide a breath specimen under the Road Traffic Act 1988.
Contractual duty: In R v Pittwood [1902] TLR 37, a railway crossing keeper who failed to close the gate was convicted of manslaughter when a person was killed by a train.
Duty arising from a special relationship: Parents owe a duty to their children (R v Gibbins and Proctor [1918] 13 Cr App R 134).
Voluntary assumption of responsibility: In R v Stone and Dobinson [1977] QB 354, the defendants took in Stone's elderly sister and assumed responsibility for her care. Their failure to summon medical help when she became seriously ill constituted the actus reus of manslaughter.
Duty arising from creating a dangerous situation: In R v Miller [1983] 2 AC 161, a squatter who accidentally set fire to a mattress and then did nothing to extinguish it was convicted of arson. Having created the danger, he was under a duty to take reasonable steps to counteract it.
Mens Rea: The Guilty Mind
The mens rea is the mental element of a crime — the state of mind that the prosecution must prove the defendant had at the time of committing the actus reus. The main forms of mens rea are intention and recklessness.
Direct intention: The defendant's aim, purpose, or desire was to bring about the prohibited consequence. This is the ordinary meaning of intention.
Oblique (indirect) intention: Where the consequence was not the defendant's purpose but was a virtually certain consequence of their actions, and the defendant appreciated this. The test was established in R v Woollin [1999] 1 AC 82: the jury may find intention where death or serious bodily harm was a virtual certainty and the defendant appreciated this. Note: the jury is not required to find intention — it is an evidential, not a substantive, direction.
Recklessness: The defendant was aware of a risk that the prohibited consequence might occur and unreasonably took that risk. Since R v G [2003] UKHL 50, the test is subjective: did this defendant actually foresee the risk? The objective test from Caldwell has been overruled.
Causation in Criminal Law
For result crimes (e.g., murder, manslaughter), the prosecution must prove that the defendant's act caused the prohibited consequence. This requires both factual and legal causation.
Factual causation: The "but for" test — but for the defendant's act, would the consequence have occurred? (R v White [1910] 2 KB 124 — the defendant poisoned his mother's drink, but she died of a heart attack before the poison took effect; the defendant was not the factual cause of death).
Legal causation: The defendant's act must be a substantial and operating cause of the consequence. It need not be the sole or main cause (R v Pagett (1983) 76 Cr App R 279). The chain of causation may be broken by a novus actus interveniens, but the original wound remains an operating cause unless it is "merely the setting in which another cause operates" (R v Smith [1959] 2 QB 35).
The thin skull rule applies in criminal law: the defendant must take the victim as they find them, including pre-existing medical conditions and religious beliefs (R v Blaue [1975] 1 WLR 1411 — a Jehovah's Witness who refused a blood transfusion).
The Coincidence Principle
The actus reus and mens rea must coincide in time — the defendant must have the guilty mind at the time of the guilty act. However, the courts have developed doctrines to address situations where they do not perfectly overlap:
Continuing act doctrine: In Fagan v Metropolitan Police Commissioner [1969] 1 QB 439, the defendant accidentally drove onto a police officer's foot and then refused to move. The court held that the actus reus was a continuing act, and the mens rea formed while the act was still ongoing.
Transaction principle: Where the actus reus and mens rea occur during a series of connected events, they may be treated as a single transaction (Thabo Meli v R [1954] 1 WLR 228; R v Church [1966] 1 QB 59).
Key Cases
| Case | Key Principle |
|---|---|
| R v Woollin(1999) | Oblique intention: virtual certainty test for finding intention |
| R v G(2003) | Recklessness is subjective: defendant must actually foresee the risk |
| R v Miller(1983) | Duty to act arises from creating a dangerous situation |
| R v White(1910) | The 'but for' test for factual causation in criminal law |
| R v Blaue(1975) | Thin skull rule: take the victim as you find them |
Exam Tips
Exam Tip
Always deal with actus reus before mens rea. For the actus reus, check: (1) Was it a voluntary act? (2) If an omission, was there a duty to act? (3) For result crimes, is causation established? Then for mens rea, identify the specific mental element required for the offence and apply the relevant test.
Common Mistake
Students often confuse the Woollin direction with a definition of intention. Woollin is an evidential direction — it tells the jury they MAY find intention, not that they MUST. Also, remember that R v G (2003) overruled Caldwell — recklessness is now always subjective in criminal law.