Section 3: Legal custody of prisoners

(1) Subject to subsection (2) of this section, every prisoner confined in a prison shall be deemed to be in the legal custody of the superintendent and shall be subject to prison discipline and regulations made under this Act whether or not he is within the precincts of the prison.
(2) In the case of a prisoner under sentence of death, the superintendent shall at such time on the day on which the sentence is to be carried out as may be fixed by the sheriff, hand over the legal custody of the prisoner to the sheriff, and from that time until the actual carrying out of the sentence-
(a) the prisoner shall be in the legal custody of the sheriff; and
(b) the sheriff shall have jurisdiction and control over that portion of the prison where the prisoner is confined and the prison officers serving therein so far as may be necessary for the safe custody of the prisoner during that period and for the purpose of carrying out the sentence and for any purpose relating thereto.
(3) Subject to this Act, every superintendent is authorised and required to keep and detain all persons duly committed to his custody by any court, judge, magistrate, justice of the peace or other authority lawfully exercising civil or criminal jurisdiction, according to the terms of any warrant or order by which any such person has been committed, until that person is discharged by due course of law .