A person may use such force as is reasonable in the circumstances for the purposes of:
• defending oneself from being attacked
• defending another person from being attacked
• defence of own property; protecting property from trespass, stopping theft/damage of personal property
• prevention of crime
• lawful arrest (citizens arrest)
There is no rule in law to say that a person must wait to be struck first before they may defend themselves.
It is not absolutely necessary that a defendant be attacked first. A man about to be attacked does not have to wait for his assailant to strike the first blow, fire the first shot or wait to be stabbed; circumstances may justify a pre-emptive strike.
In assessing the reasonableness of the force used, prosecutors will ask two questions:
• was the use of force necessary in the circumstances, i.e. Was there a need for any force at all? and
• was the force used reasonable in the circumstances, i.e. Threat to life or Continuance of force after attacker had been stopped