Criminal law, in its widest sense, includes substantive criminal law, the operation of penal institutions, criminal procedure and evidence, and police investigations (see Criminal Investigation). More precisely, the term refers to substantive criminal law – a body of law that prohibits certain kinds of conduct and imposes sanctions for unlawful behaviour.
In general, the prohibitions contained in criminal offences are concerned with protecting the public at large and maintaining the accepted values of society. These values include the preservation of morality (through such laws as the obscenity and prostitution offences); protection of the person (eg, murder and assault offences); protection of property (eg, theft and fraud offences); preservation of the public peace (eg, incitement to riot and causing a disturbance offences); and preservation of the state (eg, treason offences).
Underlying the various theories explaining the purpose of criminal law is the basic premise that criminal law is a means by which society reaffirms its values and denounces violators. A change in values entails a change in the types of conduct society wishes to prohibit. Amendments to the Criminal Code in areas such as sexual offences, abortion, pornography and punishment for murder demonstrate that Canadian criminal laws develop, at least to some extent, in response to changing social values.
Criminal law has also changed in response to technical advances, eg, recent amendments to the Criminal Code concerning theft of telecommunications, and credit card fraud and provisions regulating the use of wiretap surveillance.
The sources of substantive criminal law in Canada are limited. Most offences are created by the Criminal Code, which prohibits conviction of an offence at common law (except for the offence of contempt of court). Criminal offences are also contained in other related federal statutes, such as the Narcotic Control Act, the Food and Drugs Act, and the Young Offenders Act.
A number of federal offences and offences under provincial statutes (eg, liquor and highway control offences) and municipal bylaws (eg, parking tickets, pet control) are not criminal offences in the true sense, but are generally processed through the courts in the same general manner as criminal offences. These offences are often called “regulatory offences.”