R v Hennessy
Hyperglycaemia caused by failing to take insulin is an internal factor, so it falls within the insanity defence, not automatism.
Facts
Mr Hennessy, a diabetic, was caught driving a car that had been reported stolen while he was disqualified from driving. He said that he had not taken his insulin for several days because he was suffering from stress and depression, and that he was suffering from hyperglycaemia, high blood sugar, so he did not know what he was doing. The judge ruled that this was a plea of insanity, and Mr Hennessy pleaded guilty.
Legal principle
The Court of Appeal upheld the conviction. Lord Lane CJ said that hyperglycaemia caused by the diabetes itself, because Mr Hennessy had not taken his insulin, was caused by an internal factor, a disease, so it fell within the M'Naghten Rules. Stress and depression were not external factors of the kind that could support non insane automatism, because they are features of ordinary life. The case is usually contrasted with R v Quick, where the hypoglycaemia was caused by the external factor of insulin.
Related cases on defences: insanity, automatism and intoxication
- Attorney General for Northern Ireland v Gallagher [1963] AC 349
- Attorney General's Reference (No 2 of 1992) [1994] QB 91
- DPP v Majewski [1977] AC 443
- Hill v Baxter [1958] 1 QB 277
- M'Naghten's Case (1843) 10 Cl & F 200
- R v Bailey [1983] 1 WLR 760
- R v Burgess [1991] 2 QB 92
- R v Coley; R v McGhee; R v Harris [2013] EWCA Crim 223
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