Court of Appeal (Criminal Division) ยท Judgment of the court given by Griffiths LJ
Facts
The appellant, a diabetic, visited the new partner of his former girlfriend. He had taken insulin and, he said, had only a drink of sugar and water and nothing to eat. While at the house he struck the other man on the head with an iron bar, causing injury. His defence was that he had been in a state of automatism caused by hypoglycaemia, brought on by failing to eat after taking insulin.
History
The trial judge directed the jury that self-induced automatism was no defence. The appellant was convicted of wounding with intent to cause grievous bodily harm under s 18 of the Offences Against the Person Act 1861 and appealed.
Issue
Whether automatism that is self-induced, by failing to take food after insulin, can be a defence to (a) an offence of specific intent and (b) an offence of basic intent, and if so on what conditions.
Held
The judge's direction was wrong, but the appeal was dismissed under the proviso because no reasonable jury, properly directed, could have accepted the defence on the evidence.
Ratio
- Self-induced automatism, other than that caused by voluntary intoxication with alcohol or dangerous drugs, is a defence to an offence of specific intent if it negates the intent, and is also a defence to an offence of basic intent unless the prosecution proves that the defendant was reckless, in that he knew that his act or omission, such as failing to eat after taking insulin, was likely to make him aggressive, unpredictable or uncontrolled with the risk of endangering others, and he nonetheless ran that risk.
The judgments
Griffiths LJ (lead)
Gave the judgment of the court. Distinguished the intoxication rule in DPP v Majewski [1977] AC 443, on the ground that it is common knowledge that alcohol and dangerous drugs can make people aggressive, whereas it is not common knowledge, even among diabetics, that failing to eat after insulin may lead to aggressive or uncontrolled behaviour. Held the direction wrong, but applied the proviso because the evidence that the appellant was an automaton was flimsy and the circumstances pointed to deliberate conduct.
Key reasoning
- For an offence of specific intent such as s 18, automatism of any kind that negates the specific intent must lead to acquittal of that offence.
- The Majewski rule rests on the recklessness inherent in becoming intoxicated with substances known to cause loss of self-control; that rationale does not automatically apply to a diabetic who fails to eat, so recklessness must be proved rather than presumed.
- Hypoglycaemia caused by insulin is an external factor and so gives rise to non-insane automatism, following R v Quick [1973] QB 910.
- On the evidence, including the appellant's apparent motive, there was no real possibility that a properly directed jury would have found that he acted as an automaton.
Where it fits in the module
In the incapacity and general defences topic, Bailey shows how the law separates the involuntariness of automatism from culpability for bringing it about. It sits at the junction of the external and internal factor test from Quick and Hennessy, the intoxication rules from Majewski, and the principle of prior fault, and is used to test whether the law treats like cases alike when the same diabetic can be insane or sane depending on whether blood sugar is too high or too low.
Criticisms
- The distinction drawn with Majewski depends on assumptions about what is common knowledge, which is an unstable basis for a rule of criminal liability.
- Prior fault doctrine of this kind convicts a defendant of an offence such as unlawful wounding on the basis of recklessness as to becoming aggressive or uncontrolled, not recklessness as to the harm actually caused, so the fault does not match the offence.
- The case produces an arbitrary contrast with Hennessy: a diabetic whose condition results from failing to take insulin may be labelled insane, while one who took insulin and failed to eat may be completely acquitted.
Written with AI (claude-opus-5.5 (Claude Code writer)) on 1 November 2026, reviewed for errors by a second model (claude-sonnet-5.5 (Claude Code checker)). Read the case itself at [1983] 1 W.L.R. 760, [1983] Crim. L.R. 533. Spotted an error? Tell us.