What are the defences of “unwilled act” and “accident”?

The defences of “unwilled act” and “accident” are defences concerned with accidental, or unintended, acts or omissions by an accused person. The law absolves an accused person of criminal responsibility in two situations:

• An act or omission which occurs independently of the exercise of the person’s will (“unwilled act” defence); &
• An event which occurs by accident (“accident” defence).

These are complete defences to any offence committed by a person, including murder. That is, even if the prosecution proves you committed a murder, if it was as a result of an unwilled act or omission, or an accident, you are not guilty of the offence.

Unwilled Act defence

The defence of “unwilled act” is a defence which applies to a physical act or omission which an accused did not physically will into being. That is, an entirely unintended act or omission. This is a fairly complex defence to apply to real-life situations.

Some examples where the defence has been said to apply include:

• Cases of “non-insane automatism”, such as a case where a person who was sleep-walking killed another person in their sleep. That is, they were not conscious when they performed the act which resulted in the death of the person;
• Where a person impaled themselves on a knife that another person was holding. In these cases, it has been suggested an accused person was simply holding a knife and did not make any conscious physical action to insert the knife into the other person; &
• Where a gun held by an accused was discharged because of a faulty trigger mechanism, or because the gun was touched by the deceased person, causing it to go off not as a result of any physical action by the accused.

The unwilled act defence has been used successfully in a case where a fisherman alleged an aggressive man impaled himself on a screwdriver held by the fisherman. 

The unwilled act defence only applies to physical acts or omissions, and does not apply to unintended consequences. For example, if you stab a person by a willed act, it is no defence to say that their death was unwilled. In such a situation you would have to rely on the defence of accident, which complements the defence of unwilled act by relating to events which occur by accident. That is, the consequences of willed actions or omissions.

Unwilled act is subject to the provisions concerning criminal negligence in the criminal code. That means, for example, that if you are in charge of a dangerous thing such as a pistol, and don’t take proper care in its management, you are held criminally responsible for any harm that comes to another as a result of your failure to take care of the dangerous thing. So if for instance you were waving a pistol around and it went off unintentionally, killing someone, you might still be guilty of murder on the basis of criminal negligence.

Accident defence

The defence of accident applies to an event. That is, the consequences of a willed act or omission.

Accident comprises two tests: a subjective test, and an objective test.

The subjective test for accident is:

• The accused must not have intended the event which occurred; &
• The accused must not have foreseen the event which occurred.

The objective test for accident is:

• An ordinary person in the position of the accused must not have foreseen the event which occurred. The ordinary person is a sober person.

The prosecution need only establish that one of these tests does not apply beyond reasonable doubt in order to disprove accident at trial.

So, for example, a person might argue that by their act of punching another to the head, they did not intend, or foresee, that the person would die as a result of the punch. While this might be the case, the prosecution could argue that an ordinary person in the position of the accused would have foreseen the death, and therefore the defence does not apply.

Accident has been used in a case where an accused pushed the victim, who fell to their death through a glass window. The accused asserted, unsuccessfully, that he did not foresee the victim would fall through the window.

Accident, again, is subject to the provisions concerning criminal negligence.