custodial sentences - discretionary life sentence under s.321 criminal justice act 2003
an offender should serve a sentence of imprisonment for life when :
.The offender is convicted of a serious offence (carrying a maximum sentence of life imprisonment or minimum 10 yr)
.The offender poses a significant risk to the public of serious harm by carrying out further specific offences the maximum penalty for the offence is life imprisonment
.The court considers that seriousness of the offence, or the offence and one or more associated offence, justifies the imposition of life imprisonment