89Restriction on imposing imprisonment on persons under 21
(1)Subject to subsection (2) below, no court shall—
(a)pass a sentence of imprisonment on a person for an offence if he is aged under 21 when convicted of the offence; or
(b)commit a person aged under 21 to prison for any reason.
(2)Nothing in subsection (1) above shall prevent the committal to prison of a person aged under 21 who is—
(a)remanded in custody;
(b)committed in custody for trial or sentence; or
(c)sent in custody for trial under section 51 of the [1998 c. 37.] Crime and Disorder Act 1998.