R v Allen (Kevin) – Case Summary

R v Allen (Kevin)

Court of Appeal

Citations: [1988] Crim LR 698.


The appellant was convicted of buggery and indecent assault. He committed these offences while drunk. His defence was that at the time of the offences, he had drunk wine without realising how intoxicating it was. He had then become so drunk that he was no longer responsible for his actions. Effectively, he was in a state similar to automatism. At trial, the judge had not permitted this line of defence to go before the jury. The appellant appealed his conviction. He argued that the jury should have been allowed to consider the impact of his intoxication.

  1. Should the jury have been able to consider the effect of intoxication on the defendant’s responsibility for his actions?

The Court of Appeal dismissed the appeal and upheld the conviction. The defendant had failed to demonstrate that his intoxication was involuntary. He had voluntarily consumed alcohol, and the fact that he did not know exactly how alcoholic it was did not make his behaviour involuntary.

This Case is Authority For…

Where the defendant has voluntarily taken an intoxicant, the fact that it makes far more intoxicated than he expects does not make the intoxication involuntary.


The court affirmed the basic principle that involuntary intoxication can negative the prosecution’s case or establish a defence. In principle, it is possible to demonstrate that a defendant was so drunk they were effectively suffering from automatism.

Similarly, involuntary intoxication might negate the appearance of mens rea, or prove that the defendant had mistakenly formed a relevant belief. Ultimately, however, the burden remains on the prosecution to establish that the defendant has the relevant mens rea.