Employment of prisoners outside prisons

Subject to the rules for the time being in force, it shall be lawful to employ any prisoner under sentence of imprisonment, upon any public road, highway, street, canal or building, or upon public or government grounds or works under the supervision of a prison officer to which such prisoner 23 has been committed or removed, and every such prisoner shall, during any absence from his prison for such purpose, be deemed to be in the legal custody of the person or persons entrusted with the supervision of his employment, and to be subject to the same restraint and, in the event of misbehaviour, to the same punishment as if he had continued in prison.