This section applies where—
a person aged under 18 is convicted of a Schedule 19 offence (see section 307),
the court considers that the seriousness of—
the offence, or
the offence and one or more offences associated with it,
is such as to justify the imposition of a sentence of detention for life, and
the court is of the opinion that there is a significant risk to members of the public of serious harm occasioned by the commission by the offender of further specified offences (see sections 306(1) and 308).
The court must impose a sentence of detention for life under section 250.
The pre-sentence report requirements (see section 30) apply to the court in relation to forming the opinion mentioned in subsection (1)(c).
An offence the sentence for which is imposed under this section is not to be regarded as an offence the sentence for which is fixed by law.