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.
As soon as—
it is the duty of the Secretary of State to release him on licence.
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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—
(a)in relation to a person serving one sentence, one-half of the appropriate custodial term, and
(b)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).
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).