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Homicide is a term which describes a number of offences. These can be grouped into murder, manslaughter, infanticide, corporate manslaughter and suicide. Murder and manslaughter are the most common types. This page will use homicide to illustrate how causation works in criminal law.
Sir Edward Coke described murder, the actus reus of which will be the case study of this page, as follows:
[Where a] person of sound memory and discretion unlawfully killeth a reasonable creature in being under the King’s peace, with malice aforethought, either express or implied
The actus rei of murder and manslaughter are identical, differentiated only by differing mentes reae. ‘Killeth’ describes a voluntary act which is both a factual and legal cause of death. If the defendant’s act is involuntary, such as an act of insanity as in Bratty v A-G for Northern Ireland , or a reflex action, as in Hill v Baxter , causation can be debated no further. There is no reason why a voluntary act cannot extend to death by omission, however, the term ‘voluntary act’ does not extend to moral involuntariness (duress is no defence to murder). Where an offence requires only proof of a state of affairs, the defendant must have had adequate control over that state of affairs, according to R v Robinson-Pierre .
R v Cheshire  described causation as a question of fact for the jury, to be decided in accordance with legal principles. There are two elements to causation: factual causation and legal causation. If in the eyes of the jury, but for the defendant’s act, the result would not have occurred, factual causation can be made out. This is usually a very easy test to pass and is useful in identifying possible defendants. Legal causation requires to the jury to decide, in accordance with legal principles, where the defendant committed the offence, or in our example, caused death.
Factually, if the defendant in no way contributed to the cause of death, as was the case in R v White , where the defendant poisoned his mother’s drink in order to kill her, but she in fact died from an unrelated heart failure, causation cannot be found. Similarly, in R v Dalloway (1847), the defendant’s horse caused the death of a child, but no causation could be found as even if the defendant had been holding the reins of the horse, the death could not have been prevented.
Legally, The general rule for causation is the defendant must have contributed to the result (death) in a more than minimal way, as was said by the Court of Appeal in R v Hennigan  and R v Clarke . In each case, although subsequent events to an assault and dangerous driving occurred prior to death, the initial injury still contributed in a more than minimal way to the death. In R v Hughes , the Supreme Court decided to read a causation requirement into section 3ZB Road Traffic Act 1988 so that a defendant could not be said to have caused death without a causal contribution to that death.
Despite being rejected as a whole, this rule was echoed by the Law Commission in their Draft Criminal Code 1980, which required a more than negligible contribution to death, or an omission where a duty had been imposed for causation to be made out.
Unlike in the law of tort, where double recovery is not permitted, more than one person may be convicted of causing the same death. In R v Benge (1865), both a train driver and a foreman were responsible for the death of a track worker, and in R v Smith , the defendant’s stabbing of the victim was still found to be an operating and substantial (more than minimal) cause of death, despite that victim having been dropped several times on the way to a hospital and receiving poor treatment on arrival.
R v McKechnie  found that a defendant need not always be direct cause of death. Here, recoverable head injuries prevented life-saving treatment for a pre-existing illness being carried out, resulting in death. The defendant was found to have made a more than minimal causal contribution to the death, and the victim was to be taken as the defendant found him. If a defendant accelerates certain death, he will also be said to have caused death, as occurred in R v Dyson . Although doctors are entitled to accelerate a patient’s certain death if medically necessary, according to Ashworth and Horder.
Generally, death cannot be caused by omission. This is an extension of the principle that there is no rule of law requiring good Samaritans. For there to be a cause of death through omission, a duty must have been imposed by either common law or statute. R v Pittwood  is an example of a duty arising from a contract, and R v Gibbons and Proctor  and R v Stone and Dobinson , are examples of duties arising from relationships. Professional duties, such as those imposed on medics, can also give rise to duties: R v Adomako , the substantial case on gross negligence manslaughter, is a good example of this. Finally, death can also be caused where a danger is created and not mitigated under the doctrine of R v Miller . This doctrine was extended by R v Evans  to incorporating mere contributions to a dangerous situation, as opposed solely creating them. Omissions can sometimes be classed as part of a continuing wider act, as in Fagan v Metropolitan Police Commissioner , removing the need to justify the duty in question.
While two successive causes may sometimes both be operating and substantial, it is possible that a later cause can be classed as a supervening cause: one which renders the original act no longer a cause of death. In 1989, the Law Commission defined a supervening act as one which is immediate and sufficient, and not foreseen or reasonably foreseen by the defendant. This was also rejected, but serves as a useful guide. The law on supervening causes is mainly dictated by R v Smith  (above),which states that only in exceptional circumstances will a cause be classed as supervening. Negligent medical treatment is not enough, but exceptional medical treatment may well be, as was the case in R v Jordan , where a hospital knew of the victim’s intolerance to a particular antibiotic. In R v Cheshire , it was said that a supervening cause must convince a jury to think that the original act was made insignificant. If the subsequent event, in the eyes of the jury, could be ‘reasonably foreseen’ or ‘sensibly anticipated’, it will not absolve the defendant as a more than minimal cause of death.
Refusal of medical treatment
The Law Commission and the common law are in agreement that a refusal of medical treatment by the victim, even if unreasonable, is never a supervening cause of death. This rule was recognised in R v Holland (1841), where the victim was entitled to refuse the amputation of his finger. In R v Dear , the victim re-opened his healing wounds, but this was still not a supervening cause. Lord Lawton in R v Blaue  reasoned that the law may not recognise religious beliefs as unreasonable. The victim had refused a blood transfusion on the grounds of religious beliefs.
When under threat, it is expected that victims will try to escape from their current situation, and may injure themselves in the process. In R v Pitts (1842), it was found that escaping will not be a supervening cause unless it is so improbable that it would not be reasonably foreseeable. In R v Williams , it was found that jumping out of a car to escape a robbery was within the expected range or responses for a victim in the agony of the moment in question. The test, as explained in R v Roberts  is not whether the defendant could have foreseen the escape, but whether the escape was so daft or unexpected that no reasonable man could have foreseen it, a test not passed by the defendant, who acceptably jumped from a car to escape Roberts’ sexual advances. The advancement on this test in R v Lewis  is likely questionable.
Voluntary act of the victim
When escaping, the victim usually does so as a last resort. However, causation operates differently where the victim carries out a voluntary act which successively contributes to the defendant’s act to cause death. In R v Pagett , it was said that a reasonable act of self-preservation will not be supervening, but in Dhaliwal , a husband was not responsible for his wife’s suicide after years of mental abuse, as she was not escaping from an immediate threat and had acted through a fully informed choice. R v Kennedy (No. 2)  is a striking example of the divergence between voluntary acts and escape cases. The defendant supplied ‘class A’ drugs to the victim, who voluntarily self-administered them. The defendant was not found to have caused the victim’s subsequent death. The defendant would only have caused the death if the supply had occurred under a criminal duty of care, as occurred in R v Evans . Unusually, from R v Gnango , it could be concluded that if a defendant ‘provokes’ another to shoot a third, he can be said to have caused the third’s death. Though this may be better explained by reference to joint enterprise criminal liability.
The general rule for voluntary acts is they do break the chain of causation. The only so far unmentioned modification to be made concerns strict liability offences. According to Environment Agency v Empress Car Co , the voluntary act of a vandal to a strict liability non-pollution offence must be extraordinary to break the chain of causation, a modification not satisfied on the facts. It could be concluded that an event will be supervening if it is daft, unreasonable not a voluntary act of the victim, subject to the strict liability exception.
Other causal issues
Birth and death raise a few causal issues to be clarified. R v Poulton (1832) states than an unborn child cannot be killed, but according to A-G Reference (No. 3 of 1994) , if a child is injured whilst unborn, then dies as a result of that injury following birth, the defendant causing the original injury may still be held to have caused death. It should be noted that according to Airedale NHS Trust v Bland , a doctor does not cause death by terminating systems which provide artificial life support to patients. A final case to mention is Re A (Conjoined Twins) , which found it lawful to separate twins joined a birth, despite the guaranteed death of the weaker twin. This decision was justified differently by each of the three judges, with reference to self-defence, necessity and a lack of intent respectively.
It should also be noted that killing British subjects on foreign soil, and killing in a war situation, raise moral, legal and political issues.
Doctrine of coincidence
Not to be confused with the tort law doctrine, the criminal law doctrine of coincidence requires that the actus reus and mens rea of a crime coincide in time, or are part of the same course of conduct. In R v Thabo Meli , the defendant caused the intoxication of the victim, before rolling the victim off a cliff. The victim died not of the fall, but of later exposure. Lord Reid reasoned that although the actus reus and mens rea did not coincide with each other, the death resulted from a course of conduct which did satisfy the doctrine. Similarly, in R v Church , the defendant was said to have caused the death of the victim, who was assumed killed by the defendant’s common assault. In fact, the victim drowned after the defendant had later abandoned the injured victim in a river. Finally, in A-G Reference (No. 4 of 1980) , it was said to be irrelevant which act killed a victim who was successively pushed down a flight of stairs, had his throat cut, and who was then dismembered, all by the defendant. Of course, this situation would be made much more difficult if different defendants carried out the different acts.
There are several issues highlighted by the piecemeal common law approach to causation. It is difficult to define a clear policy to the rules. Many have concluded that the rules are unsystematic, inconsistent and don’t articulate policy consideration. Academics also disagree in certain areas, for example: Williams and Ashworth disagree on the scope of omissions (Ashworth thinks there is scope for duties to assist those in peril, enforce the law and prevent child neglect); Norrie’s view on the Law Commission’s proposals is questionable and Herring highlights a variety of causal issues.
Comparing causation to moral blameworthiness and fault (which is usually associated with mens rea) should be avoided; especially in terms of strict liability offences. However, there does seem to be a want to ensure in criminal law that someone is blamed for the death of another.