• Section 18 NFOAP97: defence of justifiable use of force may apply i.e. he was merely seeking to defend himself. Whether the force used was reasonable will be determined by the trier of the fact i.e. the jury. Section 20(4) NFOAP97: fact that a person has an opportunity to retreat before using force can be considered in determining whether the use of force was reasonable. DPP v Quinn: Section 1 NFOAP97: it is immaterial whether a belief is justified or not or reasonably held. DPP v O’Brien: 2-part test i.e. whether the accused believed the use of force was necessary; and a determination as to whether such force as was in fact used was reasonable in the circumstances as he honestly believed them to be. Where self-defence is raised, the prosecution must prove beyond reasonable doubt that the accused did not act in self-defence. AG v Keatley: deceased had been fighting with the applicant’s brother when applicant subsequently struck him, causing him to fall and sustain fatal injuries. Ct held that fatal force may be lawfully used in defence of any other person, not just one with whom one has a special relationship but that he has no right to revenge himself and if, when all the danger is past, he strikes a blow not necessary for his defence, he commits an assault and battery.