Automatism as a criminal defence

What is automatism?

Generally, at common law, a voluntary act is required to establish the actus reus of a crime. The defendant should also be conscious of their acts so that mens rea can be established. If a defendant, however, can show that they committed a crime as the result of an involuntary act they may be able to plead the defence of automatism.

In Bratty v Attorney-General for Northern Ireland (1963), Lord Denning described an act as involuntary when it is done ‘by the muscles without any control of the mind’ or ‘by a person who is not conscious of what he is doing’.

Non-insane and insane automatism

Non-insane automatism should be distinguished from insane automatism. Both involve an involuntary act; however, with insane automatism the involuntary action must have been caused by an internal factor; for non-insane automatism to be proven, the involuntary action must have been caused by an external factor.

If a defendant manages to successfully plead non-insane automatism, this serves as a complete defence and absolves them of all criminal liability. If a person successfully pleads insane automatism, a special verdict of not guilty by reason of insanity would be delivered which would usually see the defendant given a hospital order for the protection of the public.

Non-insane automatism

To successfully rely on a plea of non-insane automatism, it must be shown that:

  • there was an involuntary action arising from external source or reflex action (R v Kemp (1957));
  • the action was completely involuntary (Broome v Perkins (1987));
  • the automatism was not self-induced (R v Bailey (1983)).

It is up to the jury to decide whether the defence is made out and that the defendant was acting involuntarily due to an external factor (R v Quick (1973)).

The defence of non-insane automatism has been successfully pleaded where the defendant committed a crime because he sneezed (R v Whoolley), and where he was suffering from post traumatic stress disorder (R v T (1990)).

Where the defendant is a diabetic and commits a crime, whether he can successfully plead non-insane automatism will depend on whether it was the diabetes or the insulin which made him act illegally.

In R v Quick, the defendant committed a crime while in hypoglycaemic state because he failed to eat enough food to counterbalance the insulin he had administered. The court ruled that the insulin had made him commit the crime; this was an external factor so the non-insane automatism defence could be relied on. In R v Hennessy (1989), however, the defendant had failed to take his insulin and committed a crime while in a hyperglycaemic state. The court found it was the diabetes which caused him to offend; this was an internal factor and the defendant was thus criminally insane.

Self-induced automatism

Drunkenness and drugs

Although automatism induced voluntarily through alcohol or drugs may cause the defendant to act involuntarily or be unaware of what they were doing, it cannot normally – as a matter of public policy – be a complete defence. This is because there are a number of crimes committed under the influence of alcohol and drugs which would otherwise go unpunished.

However, there may be a partial defence in such circumstances if the accused is charged with an offence that requires a specific intent which the alcohol or drugs negated.

In R v Lipman (1969) the defendant killed a girl while under the influence of LSD. His intoxication could be used to show that he lacked the mens rea for murder because to successfully prove murder, the prosecution must show the defendant had a specific intent to kill or cause grievous bodily harm. The defendant’s conviction for manslaughter was upheld however; the Court of Appeal held that mental states induced by drink or drugs could not be a defence to manslaughter as it is a crime which does not require specific intent. In DPP v Majewski (1976) the House of Lords confirmed that unless the offence charged was one of specific intent, an alcohol or drugs defence could not apply.

Where a defendant makes a mistake because of their voluntarily induced intoxication, this also serves to negate the automatism defence. In R v O’Grady (1987) the Court of Appeal held that a defendant is not entitled to rely, so far as self-defence is concerned, upon a mistake of fact which has been induced by voluntary intoxication.

Drunkenness or drugs not self-induced

In Ross v HM Advocate (1991), the accused was charged with attempted murder. On the day in question he had drunk a can of lager which, unbeknown to him, had been spiked with several temazepam tablets and LSD. Shortly afterwards, the defendant started attacking strangers with a knife. His defence was that he had no self-control and so no mens rea. His appeal against his conviction was allowed because his absence of self-control was not self-inflicted.

Conversely, in R v Kingston (1994) the defendant was a paedophile who had been drugged by another man who wanted to take photographs of the defendant in a compromising sexual situation with a 15-year-old boy for the purposes of blackmail. The defendant pleaded a defence of involuntary intoxication. The House of Lords, however, ruled that the drugs had not sufficiently negated the defendant’s intent, as he still had the intent to commit acts of indecency with the boy even though he was under the influence of drugs.

Article written by...
Nicola Laver LLB
Nicola Laver LLB

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A non-practising solicitor, Nicola is also a fully qualified journalist. For the past 20 years, she has worked as a legal journalist, editor and author.