s 17 Duty to release certain fixed-term prisoners
(1) As soon as a fixed-term prisoner, other than one to whom Article 18 or 20A applies , has served the requisite custodial period, the Department of Justice shall release the prisoner on licence under this Article. (2) In this Article “ the requisite custodial period ” means— (a) subject to sub-paragraph (b), the custodial period specified by the court under Article 8; (b) in relation to a person serving two or more concurrent or consecutive sentences, the period determined under Article 32(2) or 33(2)