Causation in criminal liability
Causation refers to the enquiry as to whether the defendant's conduct (or omission) caused the harm or damage. Causation must be established in all result crimes. Causation in criminal liability is divided into factual causation and legal causation. Factual causation is the starting point and consists of applying the 'but for' test. In most instances, where there exist no complicating factors, factual causation on its own will suffice to establish causation. However, in some circumstances it will also be necessary to consider legal causation. Under legal causation the result must be caused by a culpable act, there is no requirement that the act of the defendant was the only cause, there must be no novus actus interveniens and the defendant must take his victim as he finds him (thin skull rule).
Factual causation
Factual causation is established by applying the 'but for' test. This asks, 'but for the actions of the defendant, would the result have occurred?' If yes, the result would have occurred in any event, the defendant is not liable. If the answer is no, the defendant is liable as it can be said that their action was a factual cause of the result.
R v White [1910] 2 KB 124 Case summary Youtube clip
Legal Causation
1. Legal causation requires that the harm must result from a culpable act:
R v Dalloway (1847) 2 Cox 273 Case summary
However, this does not apply where the offence is one of strict liability:
R v Williams [2011] 1 WLR 588 Case summary
2. The defendant's action need not be the sole cause of the resulting harm, but it must be more than minimal:
R v Benge (1865) 4 F. & F 504 Case summary
3. There must be no novus actus interveniens.
A novus actus interveniens is a new intervening act which breaks the chain of causation. Different tests apply to decide if the chain has been broken depending on the intervening party.
a). Act of a third party
The act of a third party will generally break the chain of causation unless the action was foreseeable:
R v Pagett (1983) 76 Cr App R 279 Case summary
b). The act of the victim
Where the act is of the victim, the chain of causation will not be broken unless the victim's actions are disproportionate or unreasonable in the circumstances:
R v Roberts [1971] EWCA Crim 4 Case summary
R v Williams & Davis [1992] Crim LR 198 Case summary
Where the victim is an adult of sound mind and makes a decision which causes death, this will break the chain of causation where the decision was free, deliberate and informed:
R v Kennedy [2007] 3 WLR 612 Case summary
Unless it was within the range of responses which might have been expected from a victim in his position:
R v Wallace [2018] EWCA Crim 690 Case summary
c) Medical intervention
Where medical intervention contributes to death, the courts have been inconsistent in their approach.
R v Jordan (1956) 40 Cr. App. E. 152 Case summary
R v Smith [1959] 2 QB 35 Case summary
R v Cheshire [1991] 1 WLR 844 Case summary
4. Thin skull rule (egg shell skull rule)
Under the thin skull rule, the defendant must take his victim as he finds him. This means if he has a particularly vulnerable victim he is fully liable for the consequences to them even if an ordinary person would not have suffered such severe consequences. For example if D commits a minor assault on V who has a heart condition and V suffers a heart attack and dies. D is liable for the death of V even though such an attack would result in no physical harm to some one without a heart condition.
This rule applies irrespective of whether the defendant was aware of the condition.
R v Hayward (1908) 21 Cox 692 Case summary
The thin skull rule also applies where the victim has refused medical treatment which would have saved them:
R v Holland (1841) 2 Mood. & R. 351 Case summary
R v Blaue [1975] 1 WLR 1411 Case summary
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