Any person who, having been sentenced to imprisonment or to detention in a young offenders institution, or having been committed to a prison or remand centre, is unlawfully at large may be arrested by a constable or prison officer without warrant and taken to the place in which he is required in accordance with law to be detained.

Where any person sentenced to imprisonment or to detention in a young offenders institution is, at any time during the period for which he is liable to be detained in pursuance of the sentence, absent, otherwise than with lawful authority, from the prison or young offenders institution, as the case may be, then, unless the Secretary of State otherwise directs, no account shall be taken, in calculating the period for which he is liable to be so detained, of any time during which he is so absent:

Provided that this subsection shall not apply to any period during which any such person as aforesaid is detained in pursuance of an order of any court in the United Kingdom in a prison, young offenders institution or remand centre.

Without prejudice to section 69(2) of the [1967 c. 80.] Criminal Justice Act 1967, in subsection (2) above references to a prison shall be construed as including references to a place which is the subject of a direction of the Secretary of State under section 206 of the 1975 Act (detention of children convicted on indictment).

For the purposes of this section, a person who, after being temporarily released in pursuance of rules made under section 39(6) of this Act, is at large at any time during the period for which he is liable to be detained in pursuance of his sentence shall be deemed to be unlawfully at large if the period for which he was temporarily released has expired or if an order recalling him has been made by the Secretary of State in pursuance of the rules.