... has concentrated on one of the elements of proportionality –offence-seriousness – and on one of the components of offence-seriousness – theharm done or risked by the offender’s conduct. We now ... involvement of gangs and of ‘semi-professional’ offenders, referred to by theJames Committee, continues to have a significant effect on sentences for this type of offence. For an isolated offence, by offenders ... proof of anintention to cause the prohibited harm, or proof of recklessness in that regard. Thisis sometimes termed the subjective principle of criminal liability: for most of theserious offences,...