Average Daily Populations

[Supplementary Tables A1]

The average daily prison population[i] (ADP) in 2023-24 was 7,860. This is an increase of 5.8% from the previous year (7,428) and the highest level since 2019-20 (8,198).

Figure 1 shows the fluctuations in the average daily prison population over the last two decades, as well as the close correlation between different sources of information on the overall average daily prison population. Further comparisons between these different sources are provided in the Source Comparison section.

Figure 1: The prison population has fluctuated over time, rising and falling sharply between 2017-18 and 2020-21 before stabilising then rising again in 2023-24

Long-term trends in the average daily prison population, 2002-03 to 2023-24

The following commentary relates to the new source of data produced using the cellWise method.

The average daily prison population grew from 2002-03, peaking in 2011-12 when it reached 8,134 (Figure 1). It then fell year-on-year to 7,464 in 2017-18 . In the years prior to the pandemic, theprison population grew rapidly to exceed the previous peak. In 2019-20 the average daily population was 8,198.

In 2020-21 there was a rapid decrease in the average daily prison population to 7,339. As discussed in previous editions of this publication[ii], this was likely caused by the impact of the Covid pandemic and related public health measures  on the justice system.

For the following two years, the average daily prison population remained at this lower level (7,507 in 2021-22 and 7,428 in 2022-23) before increasing to 7,860 in 2023-24.

Figure 2 shows the month-to-month changes in the prison population from January 2020 to March 2024. It shows the steady increase in the average daily population between January 2023 (7,380) and November 2023 (7,980). The average daily population fell in December 2023 but began to rise again in early 2024, reaching 7,977 in March 2024.

Figure 2: The pandemic impacts and subsequent stability in the sentenced population are followed by a period of rapid rise between January and November 2023, and in quarter one of 2024

Monthly and quarterly prison populations, January 2020 through March 2024

Legal status

[Supplementary Tables M1 and X1]

There are known discrepancies between legal status populations determined using cellWise data and the live system data in other published sources. These discrepancies arise from an undercount of remand status individuals due to the classification heirarchy applied in the construction of the cellWise data. Information on legal status should be interpreted alongside ‘live’ sources of data. See the Legal status discrepancies section for details.

The overall (average daily) prison population increased by 5.8% between 2022-23 and 2023-24. Figure 3 breaks the average daily population down by legal status[iii] category, showing that growth was driven primarily by increases in the sentenced population. The average daily sentenced population increased by 432 (+7.7%) to 6,017 in 2023-24.

Over the same period, the untried population decreased by 38 to 1,480, while the convicted awaiting sentence (CAS) population increased by 29 to 316. Overall there was a very slight decrease in the remand population on the average day from the previous year (-9 to 1,796, a fall of just -0.5%). This indicates broad stability in the overall remand population between 2022-23 and 2023-24.  In 2023-24, the remand population comprised 23% of the overall average daily prison population.

Figure 3: Population growth in 2023-24 was largely the result of a growing sentenced population. The remand population remained broadly stable overall between 2022-23 and 2023-24

Average daily populations by legal status, 2009-10 to 2023-24

Figure 4 and Figure 5 provide the monthly and quarterly remand and sentenced populations since January 2020. After an initial sharp decrease, the remand population grew rapidly to September 2020, levelling off thereafter for the remainder of 2020-21 at a higher level than pre-pandemic. After falling during 2022, remand numbers increased in early 2023 before continuing to fall slowly until March 2023.

Over 2023-24, the number of people on remand on the average day remained relatively stable at this higer level. The remand population increased between April and July 2023 and fell slightly towards the end of the year, before increasing again in early 2024.

Figure 4: The remand population has remained broadly stable at a higher level since autumn 2020

Monthly and quarterly average remand prison populations, January 2020 through March 2024

The sentenced population fell substantially and rapidly between April and July 2020 Figure 5. It was then broadly stable (between 5,500 and 5,700) until early 2023 and considerably below pre-pandemic levels. However, there was a consistent increase in the sentenced population between January and November 2023, peaking at 6,168 in December 2023.

In March 2024 the average daily sentenced population was 6,157.

Figure 5: Following a large reduction in 2020 and subsequent stability at a lower level, the sentenced population grew substantially in 2023, and between February and March 2024

Monthly and quarterly average sentenced prison populations, January 2020 through March 2024

Index Offence Groups

[Supplementary Tables M2]

This section examines the index offence groups of the (average daily) sentenced  population. A more detailed discussion of the offence categories within these groups is provided in the section Sentenced Index Offences. The alleged offences of those held on remand are discussed in the section Remand Index (alleged) Offences.

The 7.7% increase in the sentenced population between 2022-23 and 2023-24 is not distributed evenly across offence groups. The largest volume change is in the population with index offences in Group 2: Sexual Offences which increased from 1,246 to 1,392 (+146, +12%).

The populations with index offences in Group 2: Sexual offences and Group 7: Miscellaneous offences in 2023-24 now exceed pre-pandemic levels (+31% from 1,065 in 2019-20 to 1,392, and +7% from 123 in 2019-20 to 131 respectively).

There was a 17% increase in the sentenced population with index offences in Group 3: Dishonesty in 2023-24 (+50 from 294 in 2022-23 to 344 ). The size of this population had fallen each year from 2018-19, and saw a large reduction in 2020-21. While the proportionate increase in 2023-24 was large, Group 3 remains considerably below pre-pandemic levels (344 compared with 664 in 2019-20).

The population with index Group 1: Non-sexual crimes of violence offences increased in 2023-24, although at a slightly lower rate than the sentenced population as a whole. It increased by 4%, from 2,617 in 2022-23,to 2,722 in 2023-24.

The population with index Group 5: Crimes against society offences increased by 13% from 723 in 2022-23 to 817 in 2023-24. There were small absolute increases in offence groups 4, 6 and 7 between 2022-23 and 2023-24.

Figure 6: The largest sentenced population increases in 2023-24 are in offence groups 2, 1, 5 and 3.

Average daily sentenced populations by index offence group, 2009-10 to 2023-24

The changes occurring within the index offence groups continues to change the overall offence profile of the prison population. There is a consistently large (average daily) population with index offences in Group 1 and a growing population with index offences in Group 2. Over the same period, there has been an overall decline in the average daily population with index offences in groups 3 and 5. This has led to a sentenced population increasingly comprised of those with index violent and sexual offences. Together, those with index offences in Groups 1 and 2 comprised 68% of the sentenced population in 2023-24 (+1 percentage point from 2022-23).

Index sentences

[Supplementary Tables M3]

The index sentence is the longest single sentence being served in each occupancy period[iv]. Where a person in prison has multiple custodial sentences, the overall sentence length cannot be calculated from the available data. This is due to a lack of information as to whether multiple custodial sentences are to be served consecutively or concurrently. Where an individual is given multiple sentences to be served consecutively (a common occurrence with multiple short sentences), their overall sentence length will be longer than the longest individual sentence.

For clarity of presentation, the range of shorter sentence bands presented in the supplementary tables and in the interactive analysis tool[v] have been collapsed in the charts in this section.

Figure 7: There were increases in all determinate sentenced groups in 2023-24, with the largest increases occurring in the groups serving short (<1 year) and long (4-10 year) determinate sentences

Average daily populations by banded index sentence, 2009-10 to 2023-24

The overall size of the (average daily) sentenced population increased by 8% from 2023-24. Figure 7 shows this pattern was not observed equally across all index sentence bands. While the groups serving index determinate sentences grew, the population serving life and other indeterminate sentences and those on recall actually decreased by a small amount.

The (average daily) population serving index sentences of one year or less increased by the greatest proportion: +26% from 856 in 2022-23 to 1,082 in 2023-24. Meanwile the population with index sentences between one and four years increased at a rate lower than the sentenced population as a whole (+6% and +8% respectively).

Those with longer index sentences (>4 years) increased broadly in line with the sentenced population as a whole (+150, +8%). The increase in these groups is part of a long-term pattern. The 4-10 year group increased each year from 2017-18 (+472, +41%; from 1,151 in 2017-18) to 1,622 in 2023-24. The 10+ year group has grown since 2012-13 (+134, +69%; from 194 in 2012-13 to 328 in 2023-24).

The share of the sentenced population serving shorter index sentences remains below pre-pandemic levels. In 2019-20, 53% of the sentenced population had index sentences of 4 years or less (the lowest three bands in Figure 7). In 2023-24 this proportion had fallen to 44%.

Statutory Throughcare Orders

[Supplementary Tables P1]

On an average day in 2023-24, around 4% of people (263) in custody were serving one or more sentences with a Supervised Release Order[vi] (SRO) and 12% had an extended sentence[vii] (706).

Figure 8: The average daily population with an extended sentence  has steadily increased from 2018-19. The average daily population with an SRO fell during the pandemic and has remained at a lower level in 2023-24

Average daily population of people with extended sentence and Supervised Release Order (SRO) flags, 2009-10 to 2023-24

As shown in Figure 8, the average daily prison population with an SRO flag fell sharply between 2019-20 and 2020-21, having already declined slowly from 2015-16. The population increased to 270 in 2022-23, but fell to  263 in 2023-24. The proportion of the sentenced population with such conditions attached to their sentence(s) has remained relatively stable over time, varying between 4.0 and 5.5% over the past ten years.

For extended sentences, the absolute numbers and the proportionate share of the population have increased over time. The proportion with an extended sentence was between 7-8.5% from 2009-10 to 2019-20 (541) and has since increased steadily since, reaching 11.7% (706) in 2023-24.

More information on these sentence types in provided in the section Statutory Throughcare Departures.

Further population characteristics

The following two chapters of this report discuss the average daily populations of Women in Custody and Young People in Custody. Further information on other age groups, as well as information on other available protected characteristics (ethnicity, disability, sexual orientation), and breakdowns by prison establishment and armed forces history are available in the Supplementary Tables B1-8 and M1 accompanying this release.

Further exploration of these data can be conducted through the interactive analytical tool at https://scotland.shinyapps.io/sg-prison-population-statistics/.