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Police Cars

Common law police powers are judge-made laws.

How do police officers receive their powers and duties?

Police receive their duties from

  1. the common law (judge-made), and

  2. legislation (created by democratically elected representatives).

Historically, police officers have had wide-ranging duties at common law pertaining to keeping the peace and crime prevention, among other duties not typically associated with police today, such as the inspection of goods and tax collection. 

Since the institutionalization of police forces in major city centres, legislation has generally taken on a larger role in defining police powers and duties in conjunction with the general common law powers discussed above

This two-pronged conferral of police power has been the typical scheme within Canada and other common law jurisdictions, such as England and Australia.


As cities became more sophisticated and populous the different common law 

jurisdictions found their own balance between the judge-made law and legislation in relation to police powers. England, for example, has a much more comprehensive legislative scheme that authorizes police duties when compared to the Canadian legal system.


Police receive their powers from statute and the common law.

receive duties

What are common law police powers?


Presently, the common law still plays a role in giving powers to police officers in Canada. These powers can be generated by courts and are  'ancillary' to "recognized police duties" (R v McColman, at paragraph 52). An ancillary common law police power is one that is recognized in a court decision and is not authorized or created by legislation. Essentially, Canadian courts have the ability to expand police powers in order to fill legislative gaps. 


As we discuss in more depth here, once a court recognizes an ancillary common law police power in one decision, courts in future cases can uphold that decision as precedent. This cements the power as acceptable police practice.  

what are common law powers?


Examples of ancillary common law police powers include:

  • Investigative detention (R v Mann)

  • Emergency or forcible entry (R v Godoy)

  • Roadside detention ​(Dedman v R)

  • Warrantless home entry powers in response to dropped 911 calls (R v Godoy)

  • Warrantless police protective searches at the front door of a home when responding to a noise complaint (R v MacDonald)

  • Warrantless powers to engage in investigative detention, including attendant searches (R v Mann)

  • Warrantless roadblock powers in response to a 911 dispatch call near a purported crime scene (R v Clayton)

  • Warrantless drug sniffer dog searches in airports (R v Chehil), bus depots (R v Kang-Brown), high schools (R v A.M.) and on roadsides (R v MacKenzie

  • In the search incident to arrest context (Cloutier v Langlois), common law search powers have proliferated to delineate protective and evidence searches including pat-downs (R v Caslake), strip searches (R v Golden), penile swabs (R v Saeed), and cell phone searches (R v Fearon)

Image by Erik Mclean


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