Self-defence is often used as a motive for assault, manslaughter or murder. This might include an abused wife protecting herself from being assaulted by her husband or someone who attacked a burglar who was stealing from their property.

In law, a person may use 'reasonable force' to defend themselves, their property, another person, or to prevent a crime. Before deciding whether a case involving self- defence should be taken to court, lawyers have to decide whether the use of force was justified and whether it was needed at all. They also need to decide whether the use of force was excessive under the circumstances. If a case involving self-defence goes to court, it is up to the prosecution to disprove the self-defence motive.