Mission Institutionv. Khela, 2014 SCC 24:
 The jurisdiction of the provincial superior courts over prisoners in federal institutions was explained by this Court in the 1985 Miller trilogy and confirmed more recently in May. In the trilogy, Le Dain J. held that a provincial superior court has jurisdiction to hear an application for habeas corpus in order to review the validity of a detention authorized by a federal decision maker, despite the fact that alternative remedies are available in the Federal Court (Miller, at pp. 626 and 640-41). Le Dain J. concluded in Miller:
[H]abeas corpus should lie to determine the validity of a particular form of confinement in a penitentiarynotwithstanding that the same issue may be determined uponcertiorari in the Federal Court. The proper scope of the availability of habeas corpus must be considered first on its own merits, apart from the possible problems arising from concurrent or overlapping jurisdiction. The general importance of [habeas corpus] as the traditional means of challenging deprivations of liberty is such that its proper development and adaptation to the modern realities of confinement in a prison setting should not be compromised by concerns about conflicting jurisdiction. [Emphasis added; pp. 640-41.]
Thus, the availability of the writ is more important than the possibility of hypothetical issues arising as a result of concurrent jurisdiction.
 Le Dain J. also held in Miller that relief in the form of habeas corpus is available in a provincial superior court to an inmate whose "residual liberty" has been reduced by a decision of the prison authorities, and that this relief is distinct from a possible decision to release the inmate entirely from the correctional system (Miller, at p. 641). Decisions which might affect an offender's residual liberty include, but are not limited to, administrative segregation, confinement in a special handling unit and, as in the case at bar, a transfer to a higher security institution.
 Finally, Miller enhanced the effectiveness of habeas corpus by confirming that inmates may apply for certiorari in aid of habeas corpus. Without certiorari in aid, a court hearing ahabeas corpus application would consider only the "facts as they appear[ed] on the face of [the] return" or on the "face" of the decision, as the case may be, in determining whether the deprivation of liberty was lawful (D. A. C. Harvey, The Law of Habeas Corpus in Canada (1974), at p. 103). But certiorari in aid brings the record before the reviewing judge so that he or she may examine it to determine whether the challenged decision was lawful (Mooring v. Canada (National Parole Board),  1 S.C.R. 75, at para. 117). Certiorari in aid therefore operates to make habeas corpus more effective by requiring production of the record of the proceedings that resulted in the decision in question (Miller, at p. 624; Chief Justice Laskin in Mitchell v. The Queen,  2 S.C.R. 570, at p. 578).