Necessity
Necessity has two rationals
1) More Welfare will result from breaking law then keeping it.
Re Intellectually Disabled Sex Case
1) necessity to act when not practical to communicate with the assisted person. 2) The action taken must be as a reasonable person would take in all circumstances.
Three Requuirements
1)Act is needed to avoid inevitable or irreparable evil. 2)No more should be done than what is reasonably necessary for the purpose to be achieved. 3)The evil inflicted must not be disproportionate to the evil avoided.
Dudley v Stevens
Ate Cabin Boy all else they would all die
Johnson v Phillips
Cop broke law the ambulance could get through.
Re Conjoined Twins
If stayed they would both die, less detrimental option would be to let one live and one separate/die
Necessity
Revolves around the greater good or the lesser of two evils.