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Criminal | Defences

Intoxication: Criteria

Study Note | A Level

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Intoxication does not provide a defence in itself. However, it is relevant in determining whether a defendant has the required mens rea for the offence. If a defendant lacks sufficient mens rea due to his intoxicated state then he may be found not guilty.

Nature of intoxication

The law distinguishes between voluntary and involuntary intoxication.

  • Voluntary

    Voluntary intoxication occurs when a defendant chooses of his own free will to become intoxicated, either with alcohol, illegal drugs or any intoxicants.

    In general a defendant should not be excused from the consequences of their actions if they are voluntarily intoxicated. This is because the defendant is responsible for being in such a state. However, if it can be proved that the intoxication prevented him from having the necessary mens rea then the charge cannot be proved.

    Gallagher (1963)

    Defendant stabbed the victim, his wife, to death. Defendant had bought a bottle of whiskey at the same time as the knife. He had drunk most of the bottle. Defendant found guilty of murder.

    On appeal it was defendant had necessary mens rea despite his intoxication at the time of the killing.

  • Involuntary

    Involuntary intoxication covers situations where the defendant did not know he was taking an intoxicating substance. For example, this can occur if a drink is spiked or a prescribed drug has an unexpected effect.

    For involuntary intoxication to form a defence it must be proved the intoxication prevented the defendant from forming the required mens rea.


    Kingston (1994)

    Defendant, a homosexual with paedophiliac tendencies, was charged with indecent assault on a 15 year old boy. Victim and defendant were drugged without their knowledge. Defendant was photographed performing gross sexual acts with the victim, as part of a plot to blackmail the defendant.

    House of Lords found that the intoxicant had removed the inhibitions of the defendant, so he engaged in acts he would not have done if sober. However, the involuntary intoxication did not excuse this behaviour even where the defendant had been drugged by the fraud of another.

    Unanticipated strength

    Allen (1988)

    Defendant committed sexual assaults. Defendant had been drinking homemade wine. He argued it was much stronger than he realised and so he ended up so drunk he did not know what he was doing.

    It was held involuntary intoxication does not occur when the defendant voluntarily takes an intoxicant but does not realise the strength.

    Non dangerous drug

    Hardie (1985)

    Defendant was charged with arson after setting fire to a wardrobe in his flat. Defendant was depressed as his wife had told him to leave. He took some valium to calm himself down and he believed it was safe to take the tablets. Defendant had shown signs of intoxication, he slept for most of the day and then it seems set fire to the wardrobe.

    The court decided that this did not necessarily amount to voluntary intoxication. The defendant had taken a drug believing it would calm him down, which is the normal effect of valium and so he had not been reckless.

    The court found there was a distinction between dangerous drugs, ..where it is common knowledge.. [the taker] may become aggressive or do dangerous or unpredictable things... and non dangerous drugs, such as valium.

Nature of intent

The law distinguishes between basic and specific intent offences. The principle is that intoxication can be a defence to crimes of specific intent and not to those of basic intent.

Majewski (1976)

Defendant attacked victims in a pub and the police when they tried to arrest him. Defendant was very intoxicated, after drinking and taking drugs. Defendant was convicted of three offences of assault occasioning actual bodily harm, under S47 of the Offences Against the Person Act 1861 (OAPA).

House of Lords upheld his conviction. The court found that self induced (voluntary) intoxication can only be raised in defence to crimes of specific intent not basic intent offences.

  • Specific intent

    Specific intent crimes are sometimes summarised as offences requiring mens rea.

    Murder and S18 offence (under OAPA 1861) are considered to be specific intent crimes.

    Sheehan and Moore (1975)

    Defendants threw petrol over the victim, a tramp, and set fire to him, he died. Defendants were found to be too drunk to have formed the necessary mens rea to kill or cause grievous bodily harm.

    It was held the defendants did not have the necessary specific intent needed for the mens rea for murder. However, they were found guilty of manslaughter as that is a basic intent offence.

  • Basic intent

    Difficulty arises with defining which offences are of basic intent. It seems basic intent refers to general criminal intent rather than any ulterior intent that the defendant wants to achieve from his actus reus.

    Voluntary intoxication provides no defence to a crime of basic intent as the choice to become intoxicated is reckless. The defendant knows that there is a risk he will behave badly or criminally when intoxicated.

    Majewski (1976)

    Lord Elwyn Jones:.. If a man of his own volition takes a substance which causes him to cast off the restraints of reason and conscience, no wrong is done to him by holding him answerable criminally for any injury he may do while in that condition. His course of conduct in reducing himself by drugs and drink to that condition in my view supplies the evidence of mens rea, of guilty mind certainly sufficient for crimes of basic intent. It is a reckless course of conduct and recklessness is enough to constitute the necessary mens rea in assault cases....

    Basic intent crimes can be summarised as offences requiring a mens rea of recklessness.

    Some offences classified as basic intent: assault, battery, S47 and S20 offences (under OAPA 1861) and involuntary manslaughter.

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