Soto & Anor, Re (Re Section 36 of the Criminal Justice Act 1988) (Rev1) [2023] EWCA Crim 55, January 26, 2023, at paragraphs 31 to 32:

The maximum sentence for the offence of causing death by dangerous driving has been increased more than once since the offence was introduced in 1992. Originally the maximum sentence was five years’ imprisonment. This was later increased to ten years’ imprisonment. In 2004 the maximum sentence was increased to fourteen years’ imprisonment. This increase was prior to the introduction of the Sentencing Guidelines Council guideline. The significance of that increase was considered in Richardson and others [2006] EWCA Crim 3186. At [4] the court said:

Statutory changes in sentencing levels are constant. In recent years, maximum sentences have been increased (for example, drug related offences) or reduced (for example, theft). In general, changes like these provide clear indications to sentencing courts of the seriousness with which the criminal conduct addressed by the changes is viewed by contemporary society. In our parliamentary democracy, sentencing courts should not and do not ignore the results of the legislative process, and as a matter of constitutional principle, reflecting the careful balance between the separation of powers and judicial independence, and an appropriate interface between the judiciary and the legislature, judges are required to take such legislative changes into account when deciding the appropriate sentence in each individual case, or where guidance is being offered to sentencing courts, in the formulation of the guidance.

That core principle was expounded when there was no guideline in relation to the offence with which the court was concerned. There were in reality very few guidelines at all in 2006. However, the core principle is not affected by the fact that now there are guidelines for almost every offence. A change of the kind introduced by Section 86(2) of the 2022 Act must be taken into account by the sentencing court.

The court went on to review a welter of authority dealing with the extent to which an increase in a maximum sentence should affect sentencing practice at all levels of seriousness of the relevant offence. Having conducted that review the court said at [13]:

We shall avoid an anxious parade of knowledgeable citation of judicial observations from within these authorities. Consistently with our own analysis, the principle to be derived from them is that the primary object of the increase in the maximum sentence was to address cases of the most serious gravity, so as to permit the sentence to be greater than before, and in an appropriate case to be as long as or longer than the previous maximum. However, even in such cases it was not intended that the increase in sentence should reflect the consequences of the increase from ten years to fourteen years in a strictly mathematical proportion. It has long been recognised that mathematics does not provide the appropriate answer to a sentencing decision. That said, appropriate proportionality between the huge variety of offences which come within the ambit of these crimes leads to the conclusion that if the level of sentence in cases of the utmost gravity is significantly increased (as it should be) there should be some corresponding increase in sentences immediately below this level of gravity, continuing down the scale to the cases where there are no aggravating features at all. In adopting this approach, we are following earlier guidance given by this court in Attorney General’s References 14 and 24 of 1993, where the court addressed the doubling in the maximum sentence from five to ten years’ imprisonment by significantly increasing the higher, but not the lower starting points.

Since the offence of causing death by dangerous driving falls within a range of offences where death is caused by deliberate criminal behaviour the court went on to say at [14]:

We also believe that some proportion needs to be maintained between the levels of sentences for these offences, and the sentences which are thought appropriate for other offences of crimes of violence resulting in death, such as, for example, the sentences for manslaughter following a deliberate, but single violent blow, and manslaughter arising from gross negligence, which is not identical to but certainly not far removed from negligent conduct which falls “far below” expected standards, which is, of course, the criminal ingredient for dangerous driving.