Metric permalink
Prison capacity utilisation (E&W)
Part of the Rule of Law and Safety domain. Prison population as a percentage of usable operational capacity in England and Wales, measuring the margin of safety in the custodial estate.
Latest data
Latest reading
24 Aug 2026
Change between the two latest observations (10 Aug 2026 to 24 Aug 2026), in stress score.
A higher reading is treated as worse for this indicator.
Score composition
Stress score
Since the August 2026 release
What changed on this indicator between the two releases: new observation, source changed, normalisation changed.
Blended from two measured components: (2/3 weight) and trend (1/3 weight); where no trend can be computed the metric is scored on its level alone. Volatility is published as a diagnostic and does not enter the blend. Full formula on the methodology page.
Level · 2/3 weight
Percentile: this metric is scored against its own history, where today sits between its best and worst recorded years.
Trend · 1/3 weight
Measured from the direction and size of the change between the two most recent readings.
Volatility · diagnostic, not blended
9Measured from how much this indicator has swung period on period across its recorded history.
Data confidence and provenance
Confidence and source
How much weight to put on the reading, the mean data-confidence across the component metrics (source quality, recency and completeness).
Source
Prison population weekly/monthly statistics
- Update frequency
- Weekly
- Reliability
- high
Provenance
- Provider
- Ministry of Justice
- Series ID
- prison population vs usable operational capacity, E&W
- Frequency
- periodic
- Accessed
- 25 August 2026
Known weakness
Usable operational capacity is a managed administrative figure that can be adjusted by HMPPS; capacity reductions (e.g. cell refurbishments) can mechanically worsen the ratio.
Notes
Verified official value from Ministry of Justice (prison population vs usable operational capacity, E&W), accessed 2026-08-25.
Historical values
History
| Period | Value | Relative |
|---|---|---|
| 12 Aug 2022 | 97.7 | |
| 11 Aug 2023 | 98.9 | |
| 9 Aug 2024 | 98.4 | |
| 11 Aug 2025 | 98.6 | |
| Jun 2026 | 96.2 | |
| Jul 2026 | 96.4 | |
| 3 Aug 2026 | 97.3 | |
| 10 Aug 2026 | 97.4 | |
| 24 Aug 2026 | 97.6 |