s 247 Release on licence of prisoner serving extended sentence under section 227 or 228
(1) This section applies to a prisoner who is serving an extended sentence imposed under section 227 or 228 , other than a prisoner to whom section 247A applies . (2) As soon as— (a) a prisoner to whom this section applies has served the requisite custodial period , . . . (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . it is the duty of the Secretary of State to release him on licence. (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (7) In this section— “ the appropriate custodial term ” means the period determined by the court as the appropriate custodial term under section 227 or 228; “ the requisite custodial period ” means— in relation to a person serving one sentence, one-half of the appropriate custodial term, and in relation to a person serving two or more concurrent or consecutive sentences, the period determined under sections 263(2) and 264(2B) or (2E) . (8) In its application to a person serving a sentence imposed before 14 July 2008, this section is subject to the modifications set out in paragraph 15 of Schedule 20B (transitional cases).