Intoxication

teachlawhub
Apr 27
5 min read

Intoxication is a partial defence within criminal law, it provides a defence when the defendant was unable to form the mens rea for the crime as their state of mind was affected by an intoxicating substance such as:

alcohol
illegal drugs
solvents
prescribed medication
spiked drinks

The rules of this defence and availability, are quite strict this is because the courts do not want people to escape liability just because they were under the influence of an intoxicating substance. However, the law does allow intoxication to be used as a defence in some situations. The defence may apply if the defendant was so intoxicated that they could not form the required mens rea for the offence.

There are two types of intoxication:

Voluntary intoxication
Involuntary intoxication

The rules are different for each type.

Basic intent and specific intent offences

Before deciding if intoxication is a defence, the court must decide what type of offence has been committed.

Specific intent offences require a higher level of mens rea because the defendant must act with intention only. These offences are considered more serious.

Examples of specific intent offences include:

Murder
Section 18 GBH
Theft
Robbery
Burglary
Fraud

Basic intent offences are crimes where the mens rea can be intention or recklessness. Because recklessness is enough, the courts treat intoxication differently.

Examples of basic intent offences include:

Assault
Battery
Section 47 ABH
Section 20 GBH
Criminal damage
Manslaughter

This distinction is very important because voluntary intoxication can be a partial defence to specific intent crimes, but is never a defence to basic intent crimes.

Voluntary intoxication

Voluntary intoxication occurs where the defendant chooses to take an intoxicating substance of their own free will. This includes drinking alcohol, taking illegal drugs, or misusing medication.

Voluntary intoxication is only a partial defence, meaning it will not always lead to a full acquittal.

The defence is based on the idea that the defendant may have been too intoxicated to form the mens rea, but the law only provides a partial defence to the specific intent crime as the law also wants to prevent people from avoiding responsibility for their actions.

Voluntary intoxication and specific intent offences

Voluntary intoxication can be a defence to a specific intent offence if the defendant was so intoxicated that they could not form the required intention.

This rule comes from DPP v Beard, Here the defendant had been drinking heavily. He raped a girl and placed his hand over her mouth to stop her screaming, which caused her death. The House of Lords stated that intoxication can be considered where the offence requires specific intent, and the defendant was so intoxicated that they were unable to form the mens rea.

However, the court also said intoxication should not easily allow someone to escape liability, so another rule was developed.

The fall-back principle

If the defendant cannot form the mens rea for a specific intent offence, the court may still convict of a basic intent alternative.

For example:

Murder → Manslaughter
Section 18 GBH → Section 20 GBH

This is known as the fall-back rule. In reality it means that voluntary intoxication rarely leads to a full acquittal as the defendant will be charged with the basic intent alternative instead.

The reason for this rule is public policy. The courts believe people should take responsibility for getting intoxicated.

Voluntary intoxication and basic intent offences

Voluntary intoxication is not a defence to basic intent offences.

The law states that there is no defence for basic intent crimes and voluntary intoxication as the defendant was reckless in choosing to become intoxicated and recklessness is enough mens rea for basic intent crimes.

This rule comes from the case of DPP v Majewski, Here the defendant took a mixture of alcohol and drugs and became aggressive. He attacked people in a pub and later assaulted police officers. The House of Lords decided that voluntary intoxication is itself reckless behaviour. Due to the fact that basic intent offences can be committed recklessly, intoxication cannot be used as a defence.

Drunken intent is still intent

Even if the defendant is very intoxicated, there is no defence if they actually formed the mens rea.

This rule comes from the case of R v Sheehan and Moore, here the two defendants drank large amounts of alcohol and poured petrol over a homeless man before setting him on fire. The court held that intoxication is not a defence if the defendant still intended to commit the crime. As drunken/intoxicated intent is still intent in law.

The Dutch Courage Rule

The defence cannot be used if the defendant takes an intoxicating substance to give themselves courage to commit a crime. This is known as the Dutch courage rule.

This rule comes from the case of Attorney General for Northern Ireland v Gallagher, here the defendant decided that he wanted to kill his wife. He bought a knife, then drank whisky to give himself courage before committing the murder. The court decided that as he formed the intention before drinking, intoxication could not be used as a defence.

Involuntary intoxication

Involuntary intoxication happens where the defendant did not freely choose to take the intoxicating substance, or did not know they were taking it.

This can happen when:

a drink is spiked
the defendant is tricked into taking drugs
medication has an unexpected effect

Involuntary intoxication is a full defence, but only if the defendant could not form the mens rea.

It can apply to both:

basic intent offences
specific intent offences

However, the key rule is whether the defendant actually formed the mens rea.

Involuntary intoxication but mens rea is formed

There is no defence if the defendant still had the required mens rea, even though the intoxication was involuntary.

This rule comes from the case of R v Kingston, here the defendant’s drink was secretly drugged by someone trying to blackmail him. While intoxicated, he committed an indecent assault. The House of Lords held that involuntary intoxication is not a defence if the defendant still formed the necessary intent.

Stronger than expected alcohol or drugs

There is no defence if the defendant voluntarily takes an intoxicating substance but it turns out to be stronger than expected.

This rule comes from the case of R v Allen, here the defendant drank homemade wine that was much stronger than he realised and later committed offences. The courts decided that there was no defence as he chose to drink alcohol, the intoxication was still voluntary.

Spiking

Spiking is treated as involuntary intoxication.

This is where:

alcohol or drugs are secretly added to a drink
the defendant does not know they have taken the substance

There may be a full defence if:

the intoxication was truly involuntary
the defendant could not form mens rea

If the defendant still had the intention, there will be no defence.

Prescribed medication

Intoxication caused by medication may count as involuntary if the defendant was not reckless in taking the prescribed drug and was unaware of the likely effect.

This rule comes from the case of R v Hardie, here the defendant took Valium tablets given to him to calm down. Instead of making him relaxed, the drug made him aggressive and he started a fire. The court held that if the drug has an unexpected effect and the defendant was not reckless in taking it, intoxication can be a defence.

This is different from illegal drugs, which are always treated as voluntary intoxication.

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