Exculpatory Defences in Criminal Law

Abstract

The concern of this article is the theory of exculpatory defences in the criminal law of the common-law world.1 The term 'exculpatory defences' is here used to describe those general defences which negative criminal culpability despite the presence of the definitional elements of an offence. Culpability may be negatived because the actus reus occurred in a special context, as in defences like self-defence or duress. Alternatively, it may be negatived because of mental impairment, as where an incapacity to know that conduct is wrong grounds an insanity defence. Exculpatory defences arise independently of the definitional elements of offences. They are therefore separate from defences which negative actus reus or mens rea, including defences like intoxication and like insanity in the form where there is incapacity to understand the nature and quality of the conduct. Exculpatory defences are also separate from procedural defences like those which cover double jeopardy and those which control abuse of police powers. Procedural defences operate regardless of culpability, barring a conviction on grounds of defects or abuses in the handling of cases. Although self-defence and some of the other exculpatory defences have always attracted critical attention, the features of these defences as a group were neglected until recent years. For example, throughout the common-law world, texts on criminal law have typically analysed individual defences in the absence of an overall theoretical framework or with a framework of minimal proportions. This is in sharp contrast to the theoretical treatment which has long been accorded to questions of actus reus and mens rea. Consequences of this neglect are the inconsistencies and obscurities which permeate the law of the individual defences. There are now signs of growing and strengthening interest in the theory of exculpatory defences. This development may be a product of the attention which was earlier paid to elements of offences. Analysis of the concepts of actus reus and mens rea has clarified the role of exculpatory defences within principles of criminal culpability. Contemporary interest in these defences has also been stimulated by