As has been noted above, powers of arrest and detention in Canada are created by statute and by the common law. In this chapter we address powers of detention. Initially, it is worth noting that detention can be seen as a broad concept that might include arrest and subsequent detentions surrounding issues of pre-trial detention and incarceration as well as indefinite detentions under dangerous-offender legislation. Here, though, we will focus on "on-the-street" encounters where police powers short of arrest remain controversial.1In this area, the law is fast developing owing, it seems, to the need in our law for greater specificity in police powers since the enactment of the Charter of Rights and Freedoms.2
Generally in Canada, powers of arrest, as discussed in Chapter 4, arise where the police or the citizen either find the person committing an offence or, in the case of the police, they have reasonable grounds to believe the person has committed certain criminal offences. These powers to arrest are discussed below; for now we wish to address those other powers that enable police to detain an individual on
less than a reasonable belief of criminal offending. Since the enactment of the Charter, the Supreme Court has been active in addressing this area of the law, particularly in its recognition of powers of detention in Dedman,3Hufsky,4Mellinthin,5Ladouceur,6Mann,7and Clayton.8The scope and requirements of such powers are of central concern to this discussion. Initially, however, we will discuss statutory powers of detention before moving to discuss the common law. As we do so, we emphasize that our discussion is intended to focus on the detention aspect of the issues and not on related issues that arise, particularly in the context of search and seizure.
 In R. v. Thomsen,  1 S.C.R. 640 [Thomsen] and in R. v. Therens,  1 S.C.R. 613 [Therens], LeDain J. speaks of detention as a "restraint of liberty other than arrest" (Thomsen, ibid. at para. 8).
 Canadian Charter of Rights and Freedoms, Part 1 of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (U.K.), 1982, c. 11 [Charter].
 Dedman v. The Queen,  2 S.C.R. 2 [Dedman].
 R. v. Hufsky,  1 S.C.R. 621 [Hufsky].
 R. v. Mellenthin,  3 S.C.R. 615 [Mellenthin].
 R. v. Ladouceur,  1 S.C.R. 1257 [Ladouceur].
 R. v. Mann, 2004 SCC 52 [Mann].
 R. v. Clayton, 2007 SCC 32 [Clayton].