There are many defences available in Canadian criminal law which will result in an acquittal if accepted by a trial court. Defences are typically classified as justifications (the offence is made out but the act is justified by the surrounding circumstances) and excuses (the offence is made out but the act is excused, usually due to a lack of criminal intent). Defences are derived from statute as well as the common law.
It is important to remember that at trial, the prosecution bears the burden of proving the offence(s) against the accused beyond a reasonable doubt. The crown must prove date, time, identity, jurisdiction, in addition to the elements of the offence(s), commonly referred to as the actus reus (the guilty act) and the mens rea (the guilty mind). What this means is that if a reasonable doubt exists in relation to any of the elements of the offence(s) after the evidence is heard at trial, the accused will be entitled to an acquittal. If a judge or jury conclude that the prosecution has not proven its case beyond a reasonable doubt it will be unnecessary to consider any possible defence(s). The principle of proof beyond a reasonable doubt has been referred to as the golden thread which runs through our criminal justice system.
If the trier-of-fact concludes that the prosecution has proven its case beyond a reasonable doubt, we move on to possible defences. There must be an “air of reality” in the trial evidence to substantiate a defence. This prevents frivolous and outlandish defences from being suggested to the trier-of-fact during submissions by counsel. Some of the most common defences in Canadian criminal law are as follows:
Abandonment
Accident/Mistake
Alibi
Alternative Suspect
Automatism
Consent
Corrective Force
Duress
De Minimus
Due Diligence
Entrapment
Intoxication
Necessity
Provocation
Self-Defence/Defence of Another/Defence of Property