By Law Teacher

Intoxication and Insanity – cannot be used unless it leads to alcoholism. Intoxication and automatism – cannot be used if recklessly self induced. Intoxication and self-defence – if drunken mistake is about self defence or prevention of crime D will never have a defence. R v Hatton (2005) and R v O Grady (1987) s.76 Criminal Justice and Immigration Act It is also worth looking at how intoxication may affect other general defences. Firstly intoxication cannot be used in insanity. However, alcoholic abuse can lead to alcoholism which can be a disease of the mind. When intoxication produces insanity as defined in the M’Naughten Rules then it is these rules that apply. As far as automatism is concerned it cannot be used if the intoxication was recklessly self induced as discussed in R v Lipman previously. IN relation to self defence and intoxication if the drunken mistake is about self defence or prevention of a crime, D will never have a defence this is detailed in R v Hatton 2005 and R v O’Grady In R v O’Grady the Defendant and a friend got drunk and fell asleep. The defendant awoke and thought that his friend was attacking him and he had to counter attack in self defence by hitting his friend with an ashtray. D went back to sleep and awoke the next morning to find his friend dead. The House of Lords held that mistake could not be allowed because it was due to voluntary intoxication. The court had to balance the interests of the defence and the law in general. D was found guilty of manslaughter. This rules applies for both basic and specific intent crimes and the principle that a mistaken belief caused through D’s involuntary intoxication cannot use the defence of self-defence is now statutory and can be found in the S.75 Criminal Justice and Immigration Act 2008.

10.1.1 Insanity, Automatism and Intoxication – Introduction

Welcome to the tenth topic in this module guide – Defences! When a defendant is charged with a crime, there are several ways in which he possibly could go about attempting to exonerate himself of legal responsibility, reduce his liability or lessen his sentence. This can be done through arguing the facts of a case, arguing a case on a point of law, arguing mitigating circumstances or establishing a defence in his favour. In law, there exists many different types of defences, and one defence may fall under a multitude of categories.

This topic in this module focuses on three different defences: insanity, automatism and intoxication. These defences are all general and excusatory defences, so accordingly can be pleaded in relation to all crimes and apply where the accused could not have committed a criminal act due to an absence of criminal intent or mens rea.

Goals for this section:

  • To understand the components that must be satisfied in order to successfully raise a defence of insanity, automatism or intoxication.
  • To comprehend the difference between specific intent crimes and basic intent crimes, and how it relates to the defences.
  • To appreciate the effect of a successful plea of insanity, automatism and intoxication.

Objectives for this section:

  • To appreciate the delineation between insane automatism as established in the case of M’Naghten and non-insane automatism as defined in the case of Bratty.
  • To be able to identify the distinctions between involuntary intoxication and voluntary intoxication (and the caveat in relation to voluntary intoxication which arose in the case of Gallagher).
  • To be able to analyse and evaluate the nuances of all the defences, as required in an examination.

10.1.2 Insanity, Automatism and Intoxication Lecture

1.0 Introduction

Where the defendant is charged with a crime there are several ways he can go about attempting to exonerate himself of legal responsibility, reduce his liability or lessen his sentence. This can be done through arguing the facts of a case, arguing a case on a point of law, arguing mitigating circumstances or establishing a defence in his favour. In law, there exist many different types of defences and one defence may fall under a multitude of the categories. These categories include:

  • Complete
  • Partial
  • General
  • Special
  • Excusatory
  • Justificatory

These notes focus on three different defences: Insane automatism, non-insane automatism and intoxication. These defences are all general, excusatory defences.

2.0 Automatism

As stated above, automatism is as a general defence that can be pleaded in relation to all crimes. There are two types of automatism: Insane automatism and non-insane automatism. The distinction as to which defence applies comes from whether the cause of the defendant’s behaviour was internal or external.

2.1 Insane Automatism

Note that this is a legal defence and is not reflective of any medical condition.

2.1.1 Criteria

The criteria for the defence was established in the case of M’Naghten (1843) 8 ER 718 and is referred to as the M’Naghten rules. These set out that for a successful plea of insanity the following must be established:

  • The defendant laboured under a defect of reason;
  • Arising from a disease of the mind;
  • So that he did not know the nature and quality of his act, OR;
  • He did know that what he was doing was wrong.

Once the prosecution have established the actus reus beyond all reasonable doubt, the onus is then on the defendant to establish that he fulfils the criteria of insanity. Section 1 of the Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 requires the defendant in establishing the defence to adduce evidence from two or more registered medical practitioners.

2.1.2 Defect of Reason

This is a high standard to meet as the defendant must prove that he was deprived of his power to reason. A temporary distraction or absentmindedness will not suffice.

2.1.3 Disease of the Mind

The definition for what constitutes a disease of the mind is a legal definition confirmed in R v Sullivan [1984] AC 156, and not a medical one. A disease of the mind relates to a disease affecting the mental faculties of reason, memory and understanding, and cannot arise from an external cause.

2.1.4 Effect of Defect

There are two alternative elements that could be shown here for a plea to be successful. These are either or elements, although it may be possible to show both. Nature and Quality

This relates to the defendant’s ability to recognise what he was physically doing and the physical consequences of that. Wrong

This asks whether the defendant knows what he is doing is legally wrong, as opposed to morally wrong (R v Windle [1952] 2 QB 82).

2.1.5 Effect of a Successful Plea

The effect of a successful plea is a special verdict of not guilty by reason of insanity. The defendant will then be made the subject of a disposal order under the Mental Health Act 1983.

2.2 Non-Insane Automatism

Defined by Lord Denning in Bratty v Attorney General for Northern Ireland [1963] AC 386 as an act which is done by the muscles without any control by the mind or an act done by a person who is not conscious of what he is doing. The oft cited example here is the swarm of bees scenario quoted by Lord Goddard in Hill v Baxter [1958] 1 All ER 193, and proposed in Kay v Butterworth (1945) 61 TLR 452.

The requirement that the defendant have no control over his limbs means that in cases where the defendant retains some control, the defence will fail. This was highlighted inBroome v Perkins (1987) 85 Cr App R 321 where a diabetic suffering from a hyperglycaemic attack was charged with driving without due care and attention. He retained the ability to negotiate junctions and swerve away from vehicles and thus had some control over his body so the defence failed.

2.2.1 Effect of a Successful Plea

The effect of a successful plea of non-insane automatism depends entirely on the charge facing the defendant. If the defendant is charged with a specific intent crime he will be acquitted following a successful plea. If the charge is a basic intent crime then he will likely be acquitted but only where he was not reckless in becoming an automaton. Specific or Basic?

Up to this point in your studies you will probably understand the distinction to be that an offence with a mens rea of intention and nothing less is a specific intent crime, where as any other mens rea, such as recklessness or negligence, or even strict liability crimes are basic intent offences. Unfortunately, the distinction is not that straight forward!

The starting case point came in R v Morgan [1976] AC 182, where it was held that specific intent meant crimes with an ulterior intent. In R v Majewski [1977] AC 443, this was adapted to mean crimes where there was a purposive element to the mens rea. In R v Caldwell [1982] AC 341, the approach taken was to look at the wording of the charge, if the charge stated intention then the offence would be a specific intent crime, anything less and it would be classed as a basic intent crime. R v Heard [2008] QB 43, confused things further as the Court classed the offence of sexual assault which requires intentional touching by the defendant as a basic offence crime which followed the Morgan decision but conflicted directly with Caldwell. Reckless Defendant

If the automatism was caused by the defendant’s own doing, for example through drinking too much or consuming illegal drugs, the defence of automatism will not be available. In all other cases, regardless of whether the offence is specific or basic intent, the defendant will almost always be acquitted. The only instance in which the specific/basic distinction matters is where the defendant has been reckless in becoming an automaton. Whether the defendant has been reckless is a subjective question to be determined on a case to case basis with regard to the defendant’s knowledge of the risk.

Where the defendant self induces his automatism, but does so my taking a substance which is usually known to have a soporific effect then he will not be deemed to have been reckless.

2.3 Insane vs. Non-Insane Automaton

The effect of a successful plea of insane automatism is a ruling of not guilty by reason of insanity. In the past this verdict meant only one thing for the defendant and that was a hospital order, under which the defendant would be detained in a psychiatric hospital for an indefinite period of time. Considering that defendants such as Hennessy who are perfectly sane individuals suffering from a very common and non-psychiatric related medical condition would have been subjected to this order it can be seen that this was very undesirable. Accordingly, once the death penalty had been abolished most defendants historically have been reluctant to plead this defence, often choosing to take a guilty verdict for a crime in law that they were not responsible for as the incarceration was preferable than being locked up in hospital with no set release date and the stigma such a detainment would carry.

Even though this compulsory hospital order is no longer in place, the special verdict carries a lot of stigma, even today, and can still result in incarceration in a psychiatric hospital if deemed necessary. The effect of this ruling in contrast to the not guilty verdict of non-insane automatism makes the distinction between the two defences crucial, with defendants seeking to argue wherever possible that an external factor caused their automatism, for example, the drugs not the disease. Consider the following case of R v T [1990] Crim LR 256. Here, the defendant was suffering from post-traumatic stress disorder following from being raped. They had committed a robbery and stabbed the victim. In pleading their defence the judge held that the post-traumatic stress was caused by the external factor of the rape and thus was automatism.

4.0 Intoxication

The term intoxication is restricted to referring only to intoxication by alcohol and dangerous drugs. Dangerous drugs were defined in Hardie as those which are known to give rise of unpredictable or aggressive actions by their consumer.

4.1 Dangerous Drugs

Bailey sets out that dangerous drugs will never include prescription medication, even where the medication is not prescribed to the defendant and, or is taken to excess. In these cases the correct defence is non-insane automatism.

4.2 Involuntary Intoxication

A defendant will be classed as involuntarily intoxicated where he is not aware he is consuming an intoxicant, for example, in cases of spiked drinks.

Hardie further establishes that a defendant will also be taken to be involuntarily intoxicated where he has voluntarily taken drugs that are usually understood to have a soporific effect but highly unusually have an opposite effect.

In these situations, the defendant will only be afforded an defence where his intoxication deprived him of the ability to form the mens rea for his committed offence. Where the defendant does still form the mens rea of the offence then he will be guilty regardless of any intoxication. In cases where drink or drug lowers the inhibitions of the defendant so that they act in a way which they would not sober, they nevertheless often have the mens rea of the crime. Consider for example the dreaded drunken phone call to an ex-partner. This phone call would not be made sober as despite wanting to, one is able to process thoughts and conclude that this is a dreadful idea! Exposed to alcohol however this process does not occur and the phone call is made. It can be seen the desire to make the phone call exists in both scenarios. The alcohol does not remove the desire, it just prevents the thought process that usually operates to prevent one following up on this desire. In these situations, the law will not excuse the behaviour of the defendant.

4.3 Voluntary Intoxication

Where the defendant is voluntarily intoxicated and is charged with a specific intent offence and his intoxication means he did not form the mens rea of the offence then he will be not guilty. This is not because he has successfully pleaded the defence of intoxication but only because he has not formed the mens rea. If however, a basic intent alternative offence is available he will be convicted of that offence, for example, murder to manslaughter.

The only caveat on this principle arises in Attorney General for Northern Ireland v Gallagher [1963] AC 349 which states that where the defendant gets intoxicated in order to commit an offence, for example ‘Dutch courage’ then there will be no reduction in liability and the specific intent charge will remain as a matter of policy.

If the defendant is voluntarily intoxicated and charged with a basic intent offence then the jury must decide whether the defendant would have formed the mens rea had he been sober. If the defendant would not have formed the mens rea then he is not guilty. If the defendant would have formed the mens reathen he will be guilty and there is no requirement for the prosecution to further prove that the mens rea was actually formed. It can be seen here that the voluntary intoxication acts to inhibit the defendant by removing the burden from the prosecution to have to prove the mens rea.

4.4 Intoxicated Mistakes

If the defendant’s intoxicated mistake relates to an element of a provision of an offence which is phrased to include mistakes then his mistake will afford him a defence. In other instances this will not afford the defendant a defence.

10.1.3 Insanity, Automatism and Intoxication Lecture – Hands on Example

The following scenario will assess your knowledge of the defences covered here and give you a chance to have a go at applying them in relation to offences committed in a practical context. These aren’t like other areas of the law where you establish the actus reus and mens rea so it may take a bit of adjusting before you feel really confident.

Read over the following passage and pull out any material facts as you go. Once you have done this try and identify what defences may be relevant and have a go at applying them using the case law we have looked at together.

If you’re feeling a little daunted by the question don’t worry! Defences can take time to get your head around and the you’re taking all the right steps just by having a look at practice questions and familiarising yourself with them. A step by step outline answer has been provided for you that contains the points you should discuss when you go about addressing the scenario. Use this as guidance in putting together or checking your own answer. There is nothing raised in this question that we haven’t already covered so refer back to the notes to help you out. You’ll find that you have everything you need to do a really good job!

John is sleeping over his Cousin Zoe’s house before a big family wedding the next day. Zoe is really into aromatherapy and has lots of oil diffusers around the house. In John’s room Zoe puts an oil designed to aid sleep into a diffuser and it sends John to sleep really quickly. A couple of hours into the night however the scent of the oil triggers a strange reaction in John’s brain. He gets up, still asleep and walks into Zoe’s room. Zoe wakes up see’s John standing there and asks him what he is doing. John lashes out and pushes her away. The force of hitting here wakes John up and he is shocked and confused by his behaviour.

The next day at the wedding, Zoe’s boyfriend Phillip see’s her broken nose and black eye and learns what happened the night before. He is furious with John and wants to confront him and give him a broken nose and a bruised face of his own to make up for what has happened to his girlfriend. Phillip is not the tallest of men and John is over 6”4. Phillip is a little intimidated by this so decides to have a large whiskey before he confronts John in order to calm his nerves and make him seem more confident. It is an open bar and the whiskey is a particularly good blend. Phillip enjoys his drink so much he has another, and another, until he has drunk most of the bottle. He stumbles away from the bar into John and smacks him hard, breaking his nose and cutting his eye. Phillip is so drunk at this point he has little control over what he is doing and a is not actually even really aware of who John is.

Discuss any defences that John may have in relation to the GBH on Zoe and any defences Phillip may have in relation to the GBH caused to John.


  • Possible defence of automatism. Whether it will be insane or non-insane automatism will depend on whether the cause is internal or external. It will be preferable to show the cause is external where possible to avoid the special verdict and achieve a complete acquittal.
  • Burgess states that sleepwalking is an internal cause, however following R v T where possible it may be possible to argue that internal cause was trigged by an external factor. In this case, strong case that the oil triggered the chemical reaction of sleepwalking and thus is more properly aligned to Quick where the automatism was caused by the application of an external substance to the body.
  • Uncertain which way the court would proceed so consider both defences.

Insane Automatism

  • M’Naghten rules.
  • Defect of reason arising from a disease of the mind so that D did not appreciate the nature and quality of his acts or know what he was doing was wrong.
  • Applying Clarke, defect of reason was more than mere absent mindedness
  • Burgess confirms that sleep walking is a disease of the mind.
  • Applying Codere, the defendant clearly did not know the nature and quality of his acts as he was not conscious of what was happening.
  • On the facts therefore the M’Naghten rules are all satisfied and the defence of insane automatism will be available to John. The starting point is that all defendants are presumed sane so the burden is on John to establish on the balance of probabilities. If successful it will result in a special verdict of not guilty by way of insanity.

Non-Insane Automatism

  • Bratty definition. Something was done by the defendant’s muscles without the control of his mind or an act done by a person who is not conscious of what he is doing. Need to show: (i)Total loss of voluntary control as per Broome v Perkins (ii) external factor as per Quick.
  • Clear from the facts that John was not conscious of what he was doing at the time and he had suffered from a total loss of voluntary control as he was asleep. If it can be argued in line with Quick, that the external factor of the oil caused the reaction then this will be sufficient.
  • Specific/basic distinction is irrelevant here as John was not reckless in becoming an automaton and therefore will likely be acquitted.



  • Voluntary intoxication by alcohol or dangerous substance is no defence as per Hardie.
  • s.18 GBH is a crime of specific intent so if the defendant was so drunk he was prevented from forming mens rea the charge will be the basic intent alternative, in this case s.20 GBH.
  • However, a caveat applies in cases of Dutch courage such as this following the ruling in Gallagher and the defendant will be charged as if he held the mens rea at the relevant time.
  • Intoxication will therefore provide no defence to Phillip and will actually act to increase his liability to a specific intent crime when at the time of committing the offence he did not hold the requisite mens rea.