Flickety the Sentencing Guidelines allow for aggravating and mitigating factors, so judges and magistrates can impose harsher or more lenient sentences accordingly. This includes drugs and alcohol, along with many other factors like planning/intention, use of disproportionate or gratuitous violence, offending with others, racially or homophobically motivated and so on. Additionally, sentences can include treatment requirements for drugs and/or alcohol, with penalties for non-compliance. The days of offenders being cautioned or treated leniently for being drunk and disorderly, or committing offences whilst under the influence, shoud have gone now. Police do still keep drunks in cells till they have sobered up next morning, then let them go with a stern word if no offence has been committed, otherwise they'll charge them and produce them at the magistrates court.