Criminal law

October 6, 2021


Criminal law







  • Introduction

Before the 17th Century, conviction of a defendant under criminal law was based on the actus reus of the said defendant. However, English criminal courts have developed rules to include an inquiry as to the Defendant’s mens rea before convicting them. This is, arguably, because of the serious repercussions of convicting a person. This paper will discuss the extent to which recklessness constitutes mens rea and why the concept still remains controversial in criminal proceedings.

  • The meaning of mens rea

The mens rea of a crime is defined as the mental element or the state of mind the defendant possesses at the time of committing of the crime in order to be liable for an offence. In other words, “the guilty mind; criminal intent; guilty knowledge and willfulness”.

Courts have established four types of mens rea, to wit: intention to commit an offence; knowledge, which applies where a defendant is aware that his or her actions will produce undesirable results; recklessness, which entails decision to commit a risky activity despite knowing about its associated risks; Negligence, which is the least form of mens rea, applied where the defendant fails to meet a reasonable standard of behavior in his or her circumstances.

  • The History of Recklessness in English Common Law

As already stated, recklessness involves deliberately acting in flagrant actions of the consequences of one’s actions. The locus classicus in this regard is the 1957 precedent in R. Cunningham.The defendant in that case had ripped a gas meter in order to steal the money inside. However, the subject meter was connected to the neighboring property, occupied by the defendant’s mother-in-law. The removal of the gas meter by the defendant caused the gas to seep into the property, poisoning the defendant’s mother in law. The defendant was charged with the offence of endangering the mother-in-law’s life contrary to Section 23 of the Offences Against the Person Act (OAPA) 1861, which the jury convicted him for. However, the defendant appealed. 

The Court of Appeal found appeal Cunningham’s appeal and quashed his conviction. The Court established that for a defendant to be convicted for such an offence, he must have either intended to cause harm or to have been reckless as to the possibility of harm, which could he could have foreseen. This rule is commonly known as the “Cunningham Recklessness” which applied a subjective standard in assessing mens rea

Subsequently, there was a radical departure from the Cunningham standard of recklessness in the 1982 decision in Commissioner of Police of the Metropolis v Caldwell, which birthed a long-standing debate as to whether recklessness was to be assessed subjectively or objectively.  

The facts leading to that case were that the accused had developed a grudge against his employer, a hotel owner. One night, while drunk, he set the hotel on fire, causing fairly minor damage. Although, there were ten guests in the hotel at the time, they were not harmed. Nonetheless, the defendant was charged with the offence of aggravated criminal damage with intention to endanger life of recklessness as to the endangerment of life.  The trial judge instructed the jury was that voluntary intoxication was no defence in that case, leading to the Jury’s conviction if the defendant. The Court of Appeal relying on the “Cunningham Recklessness” principles, affirmed the conviction, prompting the accused to further appeal to the House of Lords. The House of Lords addressed itself to the issue of recklessness and held that the standard applicable in establishing criminal culpability should be an objective one. In the Courts view, under the objective test (reasonable man) self-induced intoxication was not be a plausible defence. Caldwell (supra) essentially introduced a separate category of recklessness in which the defendant could be held criminally liable for failing to prevent glaring a risk. 

The objective test in Caldwell precedent as applied in the Elliot case has been the subject of criticism from academic scholars all over Europe and in later cases courts became reluctant to uphold it. For example, it no longer governed the English law of manslaughter as decided in the Adomako (infra) case.

In R v. Adomako, the defendant was carrying out an eye operation on a patient which required he place the patient under a general anaesthetic. During the operation, under the defendant’s supervision, a crucial tube disconnected from the ventilator causing the patient to die from cardiac arrest. Both the trial court and Court of Appeal held that in cases of manslaughter by criminal negligence involving a breach duty of, the ordinary common law principles of the law of negligence applied. That is to say, there must be an existing duty of care owed by the defendant, the breach of which leads to harm.

The contentious issue arising from the reason discussed above is whether a gross negligence, which could be characterized as a civil breach of care, should lead to imposition of criminal liability on a defendant.

  • Recklessness as a form of Gross Negligence

From the authorities discussed above, it emerges that the terms reckless and gross negligence were treated as being synonymous. As such there was a need to hold the defendant liable for negligence but a higher degree that was needed to convict the defendant. During cases decided in the 19th century, the difficulty was not finding a defendant guilty of negligence that amounted to recklessness (gross negligence as used interchangeably by other judges). The difficulty was in determining how serious the negligence must be before conviction was warranted.

There was also the difficult question of whether an objective test ought to apply, requiring that the defendant lives up to a particular standard, or whether a defendant could avoid liability as long as he did his incompetent best.  

With time, English law began to borrow from Australian jurisprudence which found the Cunningham test more suitable. For instance, the Court in, Royall case, while adopting the approach held that the “Caldwell Recklessness” would only be suitable when considering mens rea element of recklessness indifference to death . The Court critiqued that to require foresight of the probability or likelihood of death, the test had to be akin to that of the mens rea element of malice aforethought in murder at common law which required at least foresight of death or probability of grievous bodily harm. 

The Australian High Court further applied a subjective approach in Boughey v R. In this case a medical practitioner was having consensual although somewhat unconventional sex that involved strangulation and he strangled his partner to death. The court held that the relevant question was not whether some hypothetical reasonable person in the position of the defendant would have appreciated the consequences but rather what the particular defendant, with his or her actual knowledge and capacity ought to have known in the circumstances in which he or she was placed. 

It seems that the Australian courts had a problem with the “Caldwell Recklessness” for the reason that the objective recklessness applied in it was over-inclusive as it included both the capable and the incapable defendants without taking into account the incapacity of the latter as earlier demonstrated in the Elliot case. According to their reasoning, to require an obvious risk was to impose an unjustified risk which in consequence was a great departure from the standards expected of a reasonable person and which was not the original intent of the founders of the “reasonable man” test. 

In essence, it is right that the requirement of an obvious risk or recklessness was applied in the Boughey case as the culpability consisted in failing to advert to the obvious –a risk which would have been obvious to the reasonable and capable adult. As it was right in respect of capable defendants especially those who fail to recognise an obvious risk due to voluntary intoxication such as the Caldwell itself. However, it failed its purpose and led to injustice in Elliott v C. 

The adoption of the Australian High Court’s reasoning finally began to reflect itself in later decisions of the English Courts when they began to apply objective recklessness only to criminal damage akin to that in the Caldwell case while applied subjective recklessness in respect of other crimes that were committed recklessly. A good example is the landmark case of R v Gemmell and Richards. The House of Lords, while affirming the need to subjective mens rea, considered the fact that the accused person in that case had been charged with a serious offence, and trying him based on an objective mens rea would lead to obvious unfairness. The Court further opined that there was no evidence of parliamentary intention to give reckless an objective standard. On this basis, The House of Lords concluded that recklessness would call for an inquiry as to whether an accused person was aware of the consequences of his action and whether they knew that it was unreasonable to act in such a manner. This was different to the law in Caldwell although substantially guided by it and thus for a defendant to be reckless in respect of criminal damage a jury must be satisfied that he had foreseen an obvious or unreasonable risk and yet had gone on take that risk. Such a definition of reckless will catch capable defendants but not those who lack capacity due to age or mental disorder. 

This also confirms that subjective mens rea is required for serious crime. However, if a capable defendant maintains that he gave no thought to an obvious risk of criminal damage because of voluntary intoxication by alcohol or dangerous drugs he will be criminally liable as decided in R v Majewski on presumption of recklessness.

  • Conclusion

From the foregoing analysis, it can be concluded that the concept of reckless is a controversial one, when applied in assessing mens rea. This is because it could lead to great unfairness if all the circumstances surrounding an alleged offence are not taken into account. To mitigate such an undesirable result, widely celebrated English jurisprudence, has settled that it is imperative for a subjective test to be applied in assessing recklessness in any given case. By so doing, courts are able to carefully weigh all the evidence led by an accused person in relation to their liability.   



Generally, in criminal law it is the burden of the prosecution to establish that the defendant is guilty beyond reasonable doubt. On the other hand, criminal law affords a defendant a plethora of defenses which may either result in complete exoneration, an acquittal or reduce the severity of the offense he or she is charged with. Some of these defenses can be categorized as common law to mean defenses are created by law and among them are the defenses of insanity and automatism. Insanity can generally be defined as the state of a seriously mentally ill mind or in simple term “madness”. Insanity is pleaded as a defense that proves that the defendant did not have mens rea when committing the offence he or she is being charged with. However, insanity was not always a defense as shall be covered below.

Historical development of Insanity and Automatism as Defenses

The defense of insanity has aroused more discussion than the question of the responsibility of the insane for crime. This because the defense of insanity can be pleaded as a defense to any crime which requires mens rea. The cause for the difficulty of developing a sufficient jurisprudence and policy for this defense lies in the fact that there is a failure to sufficiently recognize the fundamental principle underlying mental incapacity. That is, insanity is really not to be assessed as a question of law but one of fact. The question of law that arises after insanity has been factually proven is criminal liability of the defendant pleading insanity. Navigating through the history of insanity, insanity was pleaded in the earlier law, not as a disease affecting the state of the mind but as an Act of God or possession by demonic influences. This was owing to the rigid and staunch nature of the Catholicism in old England that referenced everything to religion and even practiced exorcisms. 

It was not until the early 19th century that insanity began to be studied as a disease that required and could be treated by the medical professionals. Before then it even sounded absurd that an insane person was to be treated like any other sick person and this was reflected in Justice Doe’s observation in State v. Pike when he quoted a declaration by the Lord Chancellor, made in the House of Lords in 1862, “The introduction of medical opinions and medical theories into this subject has proceeded upon the vicious principle of considering insanity as a disease.”

In commenting to the above statement, Mr. Justice Doe stated thus:

“This remark indicates how slowly legal superstitions are worn out, and how dogmatically the highest legal authorities of this age maintain, as law, tests of insanity, which are medical theories differing from those rejected by the same authority, only in being the obsolete theories of a progressive science.”

The defence of insanity was finally laid out in the M’Naughten Rules laid down by the House of Lords in 1843:

“To establish a defense on the ground of insanity, it must be clearly proven that at the time of committing the act, the defendant was laboring 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.”

The House of Lords further held that the burden of proving insanity on a balance of probabilities laid on the defendant and if the test was met, then the court is to declare a special verdict of “not guilty by reason of insanity.”

Summary of R v M’Naghten

In January 1843, at the parish of Saint Martin, Middlesex, M’Naghten shot Edward Drummond who he delusionary believed to be the British Prime Minister Robert Pell and fatally wounded him. When the victim died five days later, M’Naghten was charged with his murder and he pleaded not guilty by reason of insanity. 

At trial, witness and expert evidence al pointed to the fact that although a person of sound mind, M’Naghten was affected by morbid delusions and even though he possessed a moral perception of right and wrong, the delusions were carried out beyond the control of M’Naghten himself leaving him with no such perception. Accordingly, he was incapable of exercising control over his actions whilst under the influence of his delusions. His delusions grew until they peaked with the shooting of Drummond. Medical evidence also showed that a man was capable of suffering such delusions silently but had the potential to break out into violent episodes. 

M’Naghten was found not guilty and later on at a meeting of the House of Lords, the M’Naghten Rules were formed that defined insanity. The rules provide that to successfully plead insanity, the defendant must show that:

(i)He labored under such a defect of reason (ii) caused by a disease of the mind (iii) and he did not know the nature and quality of his acts or that he did not know what he was doing was wrong.

Akin to insanity, automatism is also a common law defense available for all crimes. It provides that if a person lacks total control of his body, which was not by his own fault or doing, at the time of committing a criminal act, then the defendant may plead automatism which if proven by sufficient evidence would amount to acquittal. Note that there is no special verdict as the verdict is full acquittal. 

The common concept that both these two defenses (insanity and automatism) share is the concept of complete incapacity. Furthermore, they are so related in that if there is to be a reform of the rules applying to one, then reform must be applied to the other. 

Disease of the Mind

The first important thing to always keep in mind is that disease of the mind does not necessarily mean a disease of the brain. It is not to be constructed as a medical term. Rather it requires the defendant pleading it to show proof that he was suffering from a disease, which can either be a physical disease or one of the brain, which affected the functioning of his mind. The concept of the disease of mind has its roots in English law. It is shown that this concept laid foundation in the M’Naughten rules but over the years was more developed and better defined to avoid a heavy task on the jury and courts to apply it due to its broad ambiguity. 

Over time, the M’Naghten rules proved unreliable and in turn attracted criticism from academic scholars due to the multifold interpretations that came with it. Some courts required that there exists impaired reasoning by the defendant’s reasoning for both common law defenses to succeed while others argued that the mere failure to use reasoning, or the inability to control compulsions or a momentary lapse of concentration was not enough. 

While “disease of the mind” remained to be a medical condition interpreted to mean a mental impairment or misfunctioning caused by a medical condition in the medical profession, in judicial practice non-brain conditions such as epilepsy, diabetes and even sleepwalking were and still are accepted as conditions that can result into insanity even though they are not considered mental conditions in the field of medicine. This new development was set by a few precedents which shall be discussed herein after.

R v Kemp 

During a blackout, Kemp attacked his wife with a hammer causing her grievous bodily harm. Medical evidence proved he was suffering from a physical condition called Arterial-sclerosis, a condition which restricted the flow of blood into the brain. This condition caused a temporary lapse of consciousness. 

Devlin J ruled that for the purposes of the insanity defense, a disease of the body that also affected the operation of the mind was no different from a disease of the mind. He also held that it was irrelevant whether the condition of the mind was curable or not, transitory or permanent. He refused the jury’s verdict of guilty but insane. In his exact words, “the law is not concerned with the brain but with the mind, in the sense that ‘mind’ is ordinarily used, the mental faculties of reason, memory and understanding.”

According to the M’Naghten rules, it must be established that the impaired reasoning is caused by a disease of the mind. A causal link must be established between this and an underlying disease. The meaning of the term ‘disease of the mind’ was held to be a legal rather than a psychiatric question. Whether a particular type of condition is to be characterized as a disease of the mind is a question of law to be guided by the judicial officer. For instance, a judicial officer will rule on whether drug-induced psychosis is a disease of the mind for the purposes of the defense. The jury will determine on the basis of the evidence led whether the defendant was suffering from a disease of the mind, at the time of the offence, which resulted in the requisite incapacities. 

Bratty v A-G for N. Ireland 

The defendant was suffering from a nervous system disease called the psychomotor epilepsy and during a mental blackout he killed a girl. The judge directed the jury that since the defense of automatism was not available to the defendant, it considers the defense of insanity. the jury rejected the insanity defense and the defendant was convicted. However, Lord Denning held that this was not a misdirection and stated obiter that the major diseases such as schizophrenia which the doctors refer to as psychosis passed the test of diseases of the mind. In his words, “It seems to me that any mental disorder which has manifested itself in violence and is prone to recur is a disease of the mind. At any rate it is the sort of disease for which a person should be detained in hospital rather than be given an unqualified acquittal.”

R v Sullivan 

Due to a minor epileptic fit, the defendant kicked and injured a man. Akin to in Bratty case, the judge directed the jury that the defense of automatism was not available and asked it to assess on defense of insanity. the defendant was convicted and on appeal, the House of Lords led by Lord Diplock held that epilepsy was a disease of the mind because the defendant’s mental faculties were impaired to the extent of causing a defect of reason. It was irrelevant that this was an organic disease and also irrelevant that it was temporary. 

According to Diplock’s reasoning, the defense of insanity is not premised on classifying psychiatric dysfunctions but whether the dysfunction in question falls within the context of a disease of the mind. It is also important that this discussion clarifies that not all conditions which are clinically recognized as mental disorders satisfy the ‘disease of the mind’ test. Each and every case is to be assessed on its own circumstances. Consequently, where the defendant self-induces himself to a dysfunction from use of alcohol or drugs he will not successfully plead insanity. 

Insanity is relevant at three points:

  • Insanity before trial-where the accused is in custody but is insane, there’s usually a requirement that his state of mind be assessed and confirmed by two or more doctors.
  • Unfitness to Plead-This may be raised by the defense counsel, prosecution or the judicial officer. It is determined on a balance of probabilities. 
  • Insanity at the time of the offence-this is determined by application of the M’Naughten rules whereby it must be established that at the time of the offence the defendant was suffering from a defect of reason, the impaired reasoning was caused by a disease of the mind and that the impaired reasoning was such that the defendant was not aware of what he was doing or if he was aware then he did not know that his actions were criminally liable.

Automatism just like insanity requires complete incapacity. The defense of automatism can be divided into two main categories;

  • Insane automatism 
  • Non-Insane automatism

Both categories are caused by involuntary acts but what distinguishes them is that an insane automatism is caused by an internal factor while non-insane automatism by an external factor. A non-insane automatism acts as a defense that results to total acquittal while insane automatism results to a verdict of not guilty by reason of insanity. where a defense for automatism fails, then courts tend to resort for insanity as demonstrated earlier in common law. For a plea of non-insane automatism to succeed, the defendant must sufficiently show that there was an involuntary act arising from the external source or reflex action, the action was completely involuntary and the automatism was not self-induced. 




Ashworth A. and Horder, Principles of Criminal Law, (7th Edn, 2013)

Michael J. Allen Textbook on Criminal Law (Oxford University Press 2015)

Edwards JLJ, Mens Rea in Statutory Offences (Kraus Reprint 1968)


Bratty v A-G for N. Ireland [1963] AC 386

R v Hennessy [1989] 1 WLR 287

R v Kemp [1957] 1 QB 399

R v M’Naghten

R v Sullivan [1984] AC 156

State v. Pike (1843) 8 E.R. 718; (1843) 10 Cl. & F. 200

Boughey v R

Commissioner of Police of the Metropolis v Caldwell 

Elliot v Commonwealth

R v Adomako

R v Cunningham

R v Gemmell and Richards

R v Majewski

Royall v R


Ashworth A. Insanity and Automatism: a discussion paper [2013] Crim LR 787

Habib Z, “Relevance of Mens Rea in Statutory Offences” [2012] SSRN Electronic Journal

The Lord Irving of Lairg Lord Chancellor, ‘Intention, Recklessness and Moral Blameworthiness: Reflections on the English and Australian Law of Criminal Culpability’ Sydney Law Review 

Sally Cunningham, ‘Recklessness: Being Reckless and Acting Recklessly 

Kenny A and Duff RA, ‘Intention, Agency and Criminal Liability: Philosophy of Action and the Criminal Law.” (1991) 41 The Philosophical Quarterly 378

Law Commission, Criminal Liability: Insanity and Automatism-A Discussion Paper [2013]

Frankie Queen, Description and Evaluation of the defenses of insanity and automatism

Hautamaki EW, ‘The Element of Mens Rea in Recklessness and “Criminal Negligence” (19510 2 Duke Bar Journal 55 

The Lord Irving of Lairg Lord Chancellor ‘Intention, Recklessness and Moral Blameworthiness: Reflections on the English and Australian Law of Criminal Culpability’ Sydney Law Review 

Sally Cunningham, ‘Recklessness: Being Reckless and Acting Recklessly 

Kenny A and Duff RA, ‘Intention, Agency and Criminal Liability: Philosophy of Action and the Criminal Law.” (1991) 41 The Philosophical Quarterly 37 

Cunningham S, “Recklessness: Being Reckless and Acting Recklessly” (2010) 21 Kings Law Journal 445



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