Self-defence against unprovoked assault
34. (1) Every one who is unlawfully assaulted without having provoked the assault is justified in repelling force by force if the force he uses is not intended to cause death or grievous bodily harm and is no more than is necessary to enable him to defend himself.
Extent of justification
(2) Every one who is unlawfully assaulted and who causes death or grievous bodily harm in repelling the assault is justified if
(a) he causes it under reasonable apprehension of death or grievous bodily harm from the violence with which the assault was originally made or with which the assailant pursues his purposes; and
(b) he believes, on reasonable grounds, that he cannot otherwise preserve himself from death or grievous bodily harm.
Preventing assault
37. (1) Every one is justified in using force to defend himself or any one under his protection from assault, if he uses no more force than is necessary to prevent the assault or the repetition of it.
Extent of justification
(2) Nothing in this section shall be deemed to justify the wilful infliction of any hurt or mischief that is excessive, having regard to the nature of the assault that the force used was intended to prevent.