Self‐Defence and Mistake: A Way Forward

Abstract

Two friends go out together for a drinking session. They return to one of their flats, very drunk, to sleep it off. During the night one of the men wakes up, and still under the effect of the alcohol, mistakenly believes his friend is attacking him. He responds with what he thinks are a few slight blows to fend him off, and goes back to sleep. When he wakes up in the morning he finds his friend dead, the victim of a violent assault only he could have inflicted. He thought he had acted reasonably in defending himself, but he cannot remember much about it.' Is he guilty of murder, or manslaughter, or nothing at all? Sometimes the most straightforward fact situations can present disproportionate difficulties for the criminal courts. The general questions of the right to self-defence, the amount of force which can be used in self-defence, and the effect of mistakes by the actor about either of those factors, are questions still not satisfactorily solved by the courts. Cases in recent years2 have attempted to solve these problems, and have clarified the law to a certain extent, but this clarification has highlighted two particular areas of criminal legal theory where discussion and disagreement seem constant, and which would perhaps benefit from further analysis. The first is the 'objective-subjective debate.' Should the defendant's liability be judged objectively, thus expecting him to reach the objective standard of the reasonable man, or should it be judged subjectively, requiring that he personally should have intended or forseen a possible consequence or circumstance before he is held liable? If it is a question rather of the validity of a defence then the question would be whether the defendant should be expected to behave as a reasonable man would have, or is he to be judged subjectively? The second problem is the distinction between circumstances which are part of the definition of the offence; elements of the actus reus for which mens rea is required, and circumstances which are seen to constitute a valid defence. This will be referred to as the 'definition-defence debate.' These two problems overlap in the kind of fact situation illustrated above. Is the unlawfulness of the defendant's action a circumstance of the events