(1) A person will, by
force of this section, be taken to be a "serious firearm offender if the
person is convicted of a serious firearm offence (whether the offence was
committed as an adult or as a youth).
(2)
Subsection (1) does not apply in relation to a conviction of a
serious firearm offence if—
(a) the
defendant was prosecuted and punished as a principal offender in respect of
the offence under section 267 of the Criminal Law Consolidation
Act 1935 ; or
(b) the
defendant's liability in respect of the offence derives solely from the
defendant's involvement in a joint criminal enterprise (however described).