Self-Defence

Self-Defence

In a criminal case, a person who causes the death of another in self-defence will not be punished if his conduct and the force used were necessary and proportionate. 

The test for determining whether self-defence is made out is now well settled and combines both subjective and objective elements. The jury must first be satisfied whether the defendant honestly believed that he had to act as he did in order to defend himself, and then assess whether, in all the circumstances as the defendant honestly believed them to be, his response and the force he used were reasonable. This dual standard in the test for self-defence ensures that both the defendant's genuine state of mind and the overall situation are taken into account, and avoids judging the matter purely with hindsight. 

The law does not require that a person wait until the other side strikes first before responding, but the reasonableness of a pre-emptive strike must still be judged in light of the circumstances at the time. If someone swings a punch at you, you are entitled to strike pre-emptively where it is reasonably necessary to protect yourself. Even if you were the one who originally provoked the confrontation, you do not necessarily lose the right of self-defence in the ensuing violence; this depends on the particular circumstances. 

The mere fact that a person went somewhere to seek revenge does not automatically exclude the possibility of relying on self-defence, but such facts will be important factors in assessing whether the defendant was truly acting in self-defence and whether the force he used was reasonable. Moreover, self-defence does not require a person to retreat as far as possible; retreat is merely one of the factors the jury will consider in assessing whether the force was necessary. 

Honest Belief 

Honest belief is concerned with the defendant's genuine view of the factual situation, and not with his understanding or misunderstanding of the law. The defendant may use appropriate force in response to the circumstances as he honestly believes them to be. The applicable standard is that a person may use reasonable force in a situation in which he honestly believes it necessary to protect himself or others. However, the defendant's honest belief may not persist throughout; for example, if he initially had reasonable grounds but then continued to punch and kick the victim, he may be regarded as having gone beyond what was necessary. 

The defence of self-defence requires that, at the time of acting, the defendant honestly believed that he was acting in self-defence. If he had no such belief at the time, the defence will not succeed, regardless of whether the objective circumstances are later found to support self-defence. 

Proportionality 

The defensive action must be commensurate with the degree of risk created by the attack under which the defendant believed themselves to be. For example, in R v Martin [2002] 1 Cr App R 27, the defendant shot and killed an intruder, contending that he had acted out of fear and had used reasonable force to protect himself. The court, however, held that the force he used far exceeded what was necessary, and convicted him of murder. On appeal, the court pointed out that whether the force was "reasonable" is not for the defendant himself to determine, but is a matter to be decided by the jury as representatives of society. It should be noted that excessive force will cause a defence of self-defence to fail. 

In another case, the court held that where a defence of self-defence fails and the prosecution can prove that the defendant had the intent required for murder, the defendant must bear liability for murder. Under Hong Kong law, there is no separate partial defence of "excessive self-defence". 

The same principle applies to everyone, including soldiers and police officers, with no exception on account of their office. In other words, the law draws no distinction between a case of excessive self-defence and one of excessive force used in preventing crime or arresting a suspect.