Detention
Detention is a significant deprivation of a person's liberty by the state, short of arrest. The concept matters because section 9 of the Charter protects against arbitrary detention, and section 10 triggers a set of rights (to be informed of the reason, to retain and instruct counsel, to be informed of that right) on either arrest or detention. Whether a particular police interaction qualifies as a detention is a frequently litigated issue.
Mass Tsang's criminal lawyers handle Charter applications arising from arguably unlawful detentions in many of their files. For more on these protections, see our blog post on the rights of the charged or arrested.
Physical and psychological detention
Detention can be physical — the police physically prevent the person from leaving — or psychological. Psychological detention arises where police conduct would cause a reasonable person to conclude that they were not free to go. The Supreme Court in R v Grant, 2009 set out factors to consider: the circumstances giving rise to the encounter; the nature of the police conduct (including questioning, language used, physical contact, and the use of multiple officers); and the particular characteristics or situation of the individual.
Investigative detention
Brief, investigative detention is permitted at common law where police have reasonable grounds to suspect a clear nexus between the person detained and a recent or ongoing criminal offence. The Supreme Court in R v Mann, 2004 confirmed the doctrine and limited its scope. The detention must be brief, the questioning focused on the suspected offence, and any pat-down search must be limited to officer safety concerns. Investigative detention triggers Charter section 10 rights.
Detention vs. arrest
Detention is broader than arrest. An arrest is a formal taking into custody with the intent to charge or process the person for an offence. Detention can be less formal and shorter — but engages the same core Charter protections. The two concepts overlap in practice: a person being arrested is also being detained, but not every detained person is arrested.
Remedies for unlawful detention
An unlawful detention engages section 9 (arbitrary detention) and, where Charter rights are violated during the detention, section 10. Evidence obtained as a result of the breach can be excluded under section 24(2) of the Charter, applying the three-part Grant test (seriousness of breach, impact on Charter-protected interests, society's interest in adjudication on the merits).
Related glossary terms
