ABSTRACT
This chapter provides the law on duress and necessity, mistake, self-defence an on consent. It analyses the scope and limitations of the general defences and the reform proposals for the general defences. Duress is a full defence. It requires a threat of immediate death or serious injury to defendant (D) or to someone for whom D reasonably feels responsible. The defence may fail if D joined a violent criminal gang or associated with a violent criminal. Mistake of fact is not a 'defence' as such but rather a denial of mens rea. It is often used in conjunction with self-defence – an honest, mistaken belief in the need to use force is a good defence, unless D's mistake was caused by intoxication, in which case the defence fails. Self-defence is a full defence. It must be necessary for D to use some force and the amount of force used must be 'reasonable'.
