Defences in criminal law can be defined as either complete or partial defences. Complete defences will absolve the accused of all criminal guilt, while partial defences only apply to murder and will downgrade the offence to a manslaughter charge.
Complete Defences
- Claim of right: where the accused has a genuine belief that they (or someone else they are acting on behalf of) has a legitimate claim of right to the money or property allegedly stolen
- Honest and reasonable mistake of fact: where the accused possesses an honest and reasonable belief in a state of affairs which, if it existed, would mean that the accused will be innocent of any offence
- Mental illness: an accused who is severely impaired by mental illness cannot be deemed to have the requisite intent to engage in a crime
- Self-defence: if the accused had reasonable grounds to believe that they engaged in necessary self-defence and in a way that is proportionate to the threat they faced, they will not be deemed guilty
- Necessity: this is where the accused acts in a manner to prevent serious injury or harm to another person.
- Duress: where an individual acts in response to threats or external pressure
- Consent: an individual will not be guilty of sexual assault if the complainant is found to have given consent
Partial defences
- Provocation: this occurs when the victim’s action would have caused a reasonable person to act like the accused
- Diminished responsibility: is a defence that is applied when the accused suffered an abnormality of mind which impairs their mental culpability