6. Conclusions

As of 4th April 2024, the prison population was 8,138. The modelling indicates a projected range for the average daily total prison population of between 8,050 and 8,950 in September 2025.

From March 2025 onwards, measures in the Prisoners (Early Release) (Scotland) Act have reduced the sentenced population, initially by around 5%[1]. These prison population projections include the effects of the Act.

Over the course of the next few months remand arrivals, sentenced arrivals and case conclusion levels will be monitored to assess with which scenarios the actual prison population numbers are most closely aligned.

For several reasons, modelling the future prison population using the microsimulation becomes less accurate the further ahead it is projected (whether due to systematic errors in the model, inaccurate assumptions due to unforeseen circumstances, or due to changed circumstances that the model is not built to account for). Experience to date suggests that a maximum projection period of six months allows for reliable projections.

As previously highlighted, the key factors impacting changes in the prison population in the short term will be the flows into and out of the remand and sentenced populations. This is influenced by the court recovery programme, for example the resource re-allocation from summary to solemn which took place in April 2023. The modelling assumes that there will be no further changes to the number of court rooms allocated to summary and solemn procedure until at least October 2025[2].