Sch 20B para 17
(1) Where a person to whom paragraph 16 applies is released on licence under section 244 , 247A or paragraph 5 or 6, the licence shall remain in force until the date on which the person would (but for the release) have served three-quarters of the sentence. (1A) But if section 247A would (disregarding this sub-paragraph) require the release on licence of a person to whom paragraph 16 applies at any time after the end of the period referred to in sub-paragraph (1)— (a) that requirement does not apply, and (b) it is instead the duty of the Secretary of State to release the person unconditionally. (2) Sub-paragraph (1) is subject to any revocation under section 254. (3) Sub-paragraphs (1) to (2) apply in place of section 249 (duration of licence).