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Establishing a Mens Rea in Criminal Law

Info: 1865 words (7 pages) Essay
Published: 17th Jun 2019

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Jurisdiction / Tag(s): UK Law

In order to evaluate Doctor Archer’s criminal liability for the actions of injecting Dolly and Molly, it is first necessary to determine what offences he may have committed. Secondly, considering the specific scenario and relevant case law, whether Doctor Archer would be found guilty of these offences or whether he may have any defences.

The police in an investigation would be able to charge the Doctor with more than one offence. The first and most obvious offence is murder. The definition of murder comes from common law rather than legislation, and has two elements, the Actus Reus or the wrongful act, and the Mens Rea or intention element of the crime. It is this second part which has most bearing on Doctor Archer’s liability.

The facts as described give us no reason to question the Actus Reus, as we are told that a lethal amount of diamorphine was administered and that the patients were otherwise healthy, therefore it is safe to assume, with no other circumstance known, that it was the administering of the drugs that killed Molly and Dolly[1]. There was no Novus Actus Interveniens that we know of, therefore the chain of causation is not broken[2].

However, this is not enough to establish the guilt of Doctor Archer. It must also be proved that he intended to kill the two[3], or intended to cause them grievous bodily harm[4]. The intention here must be quite strong, in that Doctor Archer must have known that death or grievous bodily harm would have been a virtual certainty as a result of his actions of injecting the patients. As he is a doctor, it is fairly certain that he would (or should) have known that diamorphine in the quantities he administered it would cause death to these patients. Therefore his intention can be inferred even if he denies it[5].

However the fact that Doctor Archer had been taking prescribed drugs with disturbing side effects may have a significant effect on the Mens Rea element of murder here. There are several cases in which it has been found that intoxication, either through drugs or alcohol, can eliminate the defendant’s intention to kill. As Doctor Archer had been prescribed the drugs, and had been taking them for several months, it is fair to assume that the principle in the case of the Attorney-General of Northern Ireland v Gallagher[6] will not apply, where it was found that a man who deliberately got himself drunk before killing his wife did not have the necessary Mens Rea. However, there is another much more relevant case, that of R v Lipman[7]. In this case, a man who had taken the hallucinogenic LSD and then killed his girlfriend in a delusional state. This case raises several interesting issues relating to intent. Lipman clearly did not intend to kill the victim (although he was found guilty of manslaughter), as it was accepted that at the time he was hallucinating an entirely different scenario to that of himself and the victim. While it is unlikely that this can be said of Doctor Archer, we are told that the drug had caused derangement of though and mood. While therefore it seems likely that he knew exactly what he was doing, the effect that the drug had on his brain may still negate his intention. Also, as the drugs had been prescribed it is questionable whether he had voluntarily intoxicated himself, as it must have been that the drugs were necessary to cure another condition (possibly insomia) and therefore were in no way recreational. However, Lipman shows us that in Doctor Archer’s case, if the drugs he was taking had caused a serious instability of mind, serious enough that they might cause him to want to murder a patient, he would be found guilty of manslaughter rather than murder. This is because he must have realised that the act of injecting that amount of diamorphine was dangerous, even if he was not of an entirely sound mind at the time.

However, we need to consider the diminished responsibility test to establish whether Doctor Archer had suffered an impairment of judgment as a result of the drugs. This defence comes from s2(1) of the Homicide Act 1957,which states that: “Where a person kills or is party to a killing of another, he shall not be convicted of murder if he was suffering from such abnormality of mind (whether arising from a condition of arrested or retarded development of mind or any inherent causes or induced by disease or injury) as substantially impaired his mental responsibility for his acts and omissions in doing or being a party to the killing.”

This would only be relevant if Doctor archer were to be found to be suffering a long term abnormality of mind that was inherent (rather than a result of the chemical effect every time the drug was taken). We would need significantly more information in order to establish this, however it must also be noted that this is only a partial defence that would reduce any sentence Doctor Archer may receive to manslaughter rather than murder.

The insanity defence must be also be considered, as it could be that the long term effect of the drug Doctor Archer was taking had completely negated his intention to kill or cause GBH. The M’Naghten rules, state that “it must be clearly proved that, at the time of the committing of the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or, if he did know it, that he did not know he was doing what was wrong”[8]. It is possible that there was a long term underlying psychological problem which caused the need for Doctor Archer to take these drugs, or that the drugs themselves caused a derangement that would be deemed serious enough to mean that despite continuing to practice medicine, Doctor Archer had lost all moral sense and honestly did not know it was wrong to kill patients. Unlike diminished responsibility, this is a complete defence to the crime, however Doctor Archer would still be likely to be committed to long term psychiatric care.

The liability of Doctor Brady is based on a very different set of facts to those above. However, as was the case with Doctor Archer it is likely that Doctor Brady would be charged with murder. The Actus Reus is established as above. Again, however, the Mens Rea may be more difficult to establish. There are several prominent cases that deal with euthanasia or mercy killings, and these must be analysed in order to find out what liability Doctor Brady may have.

The first principle to look at is that of double effect. This is found in R v Adams[9], which states that although there is no particular full defence to murder in these circumstances, where a doctor has administered a drug for one purpose (for example the relief of pain) and that drug has another effect, the doctor will not necessarily be found guilty of the patient’s murder even if he knew that the drug may have the duel affect of shortening the patient’s life. It is clear that this principle is not yet fully formed and is open to much criticism and varied interpretation. However, as we do not know whether Doctor Brady administered the drug for one reason or the other it is difficult to tell in these circumstances. We are told that he injected Maud to ensure that she suffered mo further pain, therefore he believed that she was in extremis and would have died soon anyway. However, the actual amount of the lethal drug must be determined, as an amount of painkilling drug that could only cause death when administered in such a large amount would be less likely to fall under the definition of double action

Another well known unreported case against a Dr Moor, which had facts very similar to these, tells us that even if the patient is subsequently found not to have been suffering the impendingly fatal condition that the doctor believed they were, the doctor may still be found to be justified in administering drugs that hasten death. Generally though, it is not possible to say for certain whether Dr Brady would be found not guilt of murder on this basis, as the law is unclear and others have been found guilty[10].

Finally, whether the liability would be any different if the nurse had administered the drugs to Maud. This is unlikely, as a staff nurse will generally be found to be acting under the orders of a senior doctor, and we have no evidence that this would not be the case. If Dr Brady had ordered Nurse Chambers to administer a dose to Maud that he would have done otherwise, it would be likely to result in the prosecution of Dr Brady as described above,solely or possibly in conjunction with Nurse Chambers if the decision was reached jointly. However, if Nurse Chambers was adequately supervised and trained and came to a decision herself to inject the patient, which was not a decision Dr Brady would have taken, it is conceivable she would be prosecuted alone.



Tur, R The Doctor’s Defense. The Mount Sinai Journal of Medicine Vol. 69 No. 5 October 2002 pp. 317-326


Homicide Act 1957

Case Law

R v Armstrong (1989) Crim. L.R. 149

R v Cheshire (1991) 3 All E.R. 670

R v Woolin (1999) AC 82

R v Moloney (1985) 1 AER 1025

R v Nedrick (1986) 83 Cr. App. R. 267

Attorney-General of Northern Ireland v Gallagher (1961) 45 Cr. App. R. 316

R v Lipman (1969) 3 W.L.R. 819

M’Naghten’s case (1843) UKHL J16

R v Adams (1957) Crim LR 365


[1] R v Armstrong (1989) Crim. L.R. 149

[2] R v Cheshire (1991) 3 All E.R. 670

[3] R v Woolin (1999) AC 82

[4] R v Moloney (1985) 1 AER 1025

[5] R v Nedrick (1986) 83 Cr. App. R. 267

[6] (1961) 45 Cr. App. R. 316

[7] (1969) 3 W.L.R. 819

[8] M’Naghten’s case (1843) UKHL J16

[9] (1957) Crim LR 365

[10] #Tur, R The Doctor’s Defense. The Mount Sinai Journal of Medicine Vol. 69 No. 5 October 2002 pp. 317-326

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