Habeas Corpus refers to the common law prerogative writ of relief that challenges the detention of a detainee. A prerogative writ is a manner of correcting errors of jurisdiction made by inferior courts as well as correcting failures of natural justice or procedural fairness.
This prerogative writ was also imported into section 10(c) of the Charter:
10. Everyone has the right on arrest or detention...
- c) to have the validity of the detention determined by way of habeas corpus and to be released if the detention is not lawful.
Section 10(c) does not change the law of habeas corpus so much as it constitutionally entrenches it.
Burden of Proof
The onus of proof to establish the deprivation rests on the applicant while the onus to establish the lawfulness of the deprivation rests on the detaining authority.
An application for habeas corpus requires: 
- a deprivation of liberty and
- that the deprivation be unlawful.
The writ of habeas corpus requires a "generous and flexible interpretation".
- R v Forsythe, 1980 CanLII 15 (SCC),  2 SCR 268, 53 CCC (2d) 225
Re Day (1983), 62 N.S.R. (2d) 67 (NSSC)(*no link)
Wilson v R., (1986), 42 Man. R. (2d) 222 (Man. Q.B.)(*no link)
R v Reimer, (1987), 47 Man. R. (2d) 156 (Man. C.A.)(*no link)
- May, supra
- May v Ferndale Institution 2005 SCC 82 (CanLII), (2005), 3 SCR 809 at 74
- Idziak v Canada (Minister of Justice), 1992 CanLII 51 (SCC),  3 SCR 631,  S.C.J. No. 97 (QL), at par. 26
The applicant's personal attendance in court is necessary for an application of habeas corpus:
Appearance in person — habeas corpus
774.1 Despite any other provision of this Act, the person who is the subject of a writ of habeas corpus must appear personally in court.
2002, c. 13, s. 77.
Detention on inquiry to determine legality of imprisonment
775. Where proceedings to which this Part applies have been instituted before a judge or court having jurisdiction, by or in respect of a person who is in custody by reason that he is charged with or has been convicted of an offence, to have the legality of his imprisonment determined, the judge or court may, without determining the question, make an order for the further detention of that person and direct the judge, justice or provincial court judge under whose warrant he is in custody, or any other judge, justice or provincial court judge, to take any proceedings, hear such evidence or do any other thing that, in the opinion of the judge or court, will best further the ends of justice.
R.S., 1985, c. C-46, s. 775; R.S., 1985, c. 27 (1st Supp.), s. 203.
Provincial Rules of Court will have some direction on the exact process required for making application and responding to one.
Deprivation of Liberty
Occupancy of a Cell
The "double bunking" of inmates is generally not considered a from of deprivation of residual liberty. Similarly, housing an inmate in a double occupancy room instead of a usual single occupancy does not engage a deprivation of liberty.
A habeas corpus application cannot be brought to challenge house arrest bail conditions.
Sufficiency of Reasons
A decision to suspend parole must be accompanied by reasons. Where reasons are not given, the decision becomes unlawful, jurisdiction is lost, and so is reviewable under hebeas corpus.
An inmate who is transferred to a higher security level of prison must be provided with sufficient information to permit a meaningful opportunity to challenge the allegations or else jurisdiction may be lost.
See: B.R.L. v Canada,  F.C.J. No. 108(*no link)
Robert Collin v The Solicitor General of Canada,  1 F.C. 496(*no link)
Piche v Canada (Solicitor General),  F.C.J. No. 204(*no link)
- Mennes v Canada (Attorney General), 2008 CanLII 6424 (ON SC)
- R v Ethier, 2009 CanLII 11429 (ON SC), (2009), 2009 CarswellOnt 1391 (Ont. S.C.J.)
- Woodhouse v Williams Head Institution, 1999 BCCA 432 (CanLII),  BCJ 1005
- Khela v Mission Institution, 2010 BCSC 721 (CanLII),  BCJ 971