ABSTRACT
Introduction The cases in this chapter have developed the defence afforded to the defendant where his mistaken perception of an element of the offence may affect his liability. In some cases a mistake may actually negative an essential element of the offence and result in the defendant’s acquittal. In these cases the mistake is excusatory in that the prosecution fails to prove the complete offence. In other cases a mistake may offer the defendant a defence to an offence that is proved and is therefore justificatory. The offence is proved but we can excuse the defendant’s conduct in the circumstances because he was operating under a mistaken view of the situation. The category into which a defendant’s mistake falls depends on the nature of the mistake and the type of offence he is charged with.
