Criminal conspiracy

Lore & Background

In England and Wales, the common law originally treated conspiracy as an offense capable of infinite expansion, enabling courts to criminalize any new conduct deemed a sufficient threat to society, effectively acting as a legislature. This common law offense was largely abolished by the Criminal Law Act 1977, which created a statutory offense and preserved only two common law varieties: conspiracy to defraud, and conspiracy to corrupt public morals or to outrage public decency. The statutory offense, recommended by the Law Commission to replace vague common law crimes, makes it an offense to agree to pursue a course of conduct that, if carried out, would involve the commission of a criminal offense by one or more parties.

This reform aimed to ensure that only agreements to commit actual crimes were punishable, addressing the mischief that common law could criminalize conduct not itself illegal. The preserved common law offense of conspiracy to defraud was defined in the case Scott v Commissioner of Police of the Metropolis. The other preserved offense, conspiracy to corrupt public morals or outrage public decency, covers agreements to engage in conduct tending to corrupt morals or outrage decency, even if a single person could not be convicted for the same act. However, one authority notes that conspiracy to corrupt public morals lacks definitive case law and is unlikely to be prosecuted.

United States

A key characteristic of conspiracy is that the agreement itself is the crime; no steps need be taken to put the plan into effect, unlike attempts which require proximity to the full offense. Liability is continuing, meaning parties may join the plot later and incur joint liability, and repentance by a party does not affect liability unless it occurs before any overt acts are committed, though it may reduce sentence. An unindicted co-conspirator is a person alleged in an indictment to have conspired but not charged, often due to immunity or evidentiary concerns.

Constitutional Foundation and Federal Jurisdiction

The Constitution grants the Parliament of Canada exclusive authority over criminal law, meaning the Code's provisions carry uniform force across every province and territory. This federal character has a striking practical consequence: any offence defined within the Code is a federal crime that can be prosecuted wherever it occurs, whether inside Canada's borders or beyond them. In legal citations, practitioners shorten it to Cr.C. or CC in English, and C.cr. in French.

One notable procedural feature flows from this federal reach: with the single exception of treason, which carries a three-year limitation period, indictable offences face no statute of limitations at all. Prosecutors may bring charges at any point in the future. Summary offences, by contrast, must be pursued within twelve months of the alleged act.

Reader's Guide

The significance of criminal conspiracy lies in its ability to criminalize planning before any harmful act occurs, distinguishing it from attempt, which requires proximity to the full offense. However, preserved common law offenses like conspiracy to defraud remain broad, defined as an agreement by dishonesty to deprive a person of something or to injure a proprietary right.

The mens rea requires both agreement and an intention to play some part in the criminal purpose, as established in R v Anderson. Evidentiary rules allow statements or acts of one conspirator in furtherance of the common design to be admitted against another, provided independent evidence of the conspiracy exists. The offense continues to be a tool for prosecuting organized crime, terrorism, and fraud, though its scope remains subject to judicial interpretation.