(1)Subject to subsection (3) below, where—
(a)an offender has been sentenced to a term of youth custody ; and
(b)either—
(i)he has attained the age of 21 years ; or
(ii)the conditions specified in subsection (2) below are satisfied in relation to him,
the Secretary of State may direct that he shall be treated as if he had been sentenced to imprisonment for the same term.
(2)The conditions mentioned in subsection (1) above are—
(a)that the offender has attained the age of 18 years; and
(b)that he has been reported to the Secretary of State by the board of visitors of the institution in which he is detained as exercising a bad influence on the other inmates of the institution or as behaving in a disruptive manner to the detriment of those inmates.
(3)An offender who by virtue of this section falls to be treated as if he had been sentenced to imprisonment instead of youth custody is not to be so treated for the purposes of section 15 below.
(4)Where the Secretary of State gives a direction under subsection (1) above in relation to an offender, the portion of the term of youth custody imposed by the youth custody sentence which he has already served shall be deemed to have been a portion of a term of imprisonment.
(5)Rules under section 47 of the [1952 c. 52.] Prison Act 1952 may provide that any award for an offence against discipline made in respect of an offender serving a youth custody sentence shall continue to have effect after a direction under subsection (1) above has been given in relation to him.