Since, there is a wide variance in the facts of cases this application by the jury is to a very large extent dependant on the application of commonsense and community perceptions. Moreover, the law is such that the level of justifiable self-defence is significantly dependant on the level of danger presented by an attacker.
Furthermore, a defendant cannot be convicted for an offence unless the court is convinced first, that the defendant committed the act alleged by the prosecution and second, that the defendant had the intention to commit that act.
In other words, it has to be established beyond any doubt that the act was something about which the defendant was aware and had all intent to commit. Such inferences can be drawn if no other rational or reasonable conclusion can be surmised from the evidence presented by the prosecution.
"In cases where the evidence discloses a possible defence of self defence the onus remains throughout upon the prosecution to establish that the accused is guilty of the crime of murder and the onus is never upon the accused to establish this defence1." In this connection in The Queen v Howe2 it was held that, "The state of the law appears to be that once a ground is disclosed by the eviden ...