Prison population statistics

Prisons are devolved, so UK prison statistics are published separately for England and Wales (the Ministry of Justice), Scotland (the Scottish Government), and Northern Ireland (the Department of Justice).

Prison population trends in England and Wales

Since 1900, the prison population has quadrupled in size, going from just over 17,400 to around 87,300 in 2024 (the highest level recorded over this period).

During the same time, the adult population of England and Wales has more than doubled in size, so the rate of imprisonment relative to the population has increased.

Over the most recent decade, the prison population shrunk temporarily – in part due to the pandemic – however, since 2023 the prison population has exceeded the pre-pandemic level.

Source: MoJ, Offender Management Statistics Quarterly, various years

UK average annual prison population data

As outlined above, the average annual prison population was around 87,300 people in England and Wales in calendar year 2024. This was around 170 prisoners per 100,000 people aged 15 and over in the general population.

It was around 8,200 in Scotland (177 prisoners per 100,000 people aged 15 and over), and 1,900 in Northern Ireland in financial year 2024/25 (124 prisoners per 100,000 people aged 15 and over).

This means the time periods for the UK countries overlap but do not match exactly (this has been the case since 2014 when Scotland and Northern Ireland switched to publishing on a financial year basis). For simplicity, in the overview below all data will be referred to on the England and Wales calendar year basis.

Up until 2015, the UK prison population had been generally increasing in size, with the sharpest increases happening in the mid-1990s and the 2000s. After that it flattened off, and it was falling in Scotland and Northern Ireland before the pandemic. The most recent average annual prison population figures for each country in the UK were the highest levels recorded since 1900.

The chart below shows prison population change relative to 1900 (and relative to 2000 for Northern Ireland).

Source: MoJ (England and Wales) Offender Management Statistics Quarterly, various years; Scottish Government, Prison statistics and population projections; DoJ (Northern Ireland) The Northern Ireland Prison Population 2024/25

Prison population characteristics

In June 2025 in England and Wales:

• The prison population continues to age. In 2025, 4% of prisoners were under the age of 21, compared with 13% in June 2010. While 18% of prisoners were over the age of 50 compared to 9% in 2010.
• Prison sentences have been lengthening, with 48% of determinate prison sentences being over 4 years in 2025 compared with 36% in June 2010.
• Foreign nationals made up around 12% of the prison population, this rate was around the same in June 2015.
• People from minority ethnic groups made up around 27% of the prison population compared with 18% of the general population.

In September 2025, 56% of prisons in England and Wales were classified as crowded.

Prisoner costs

There are several different ways of measuring prisoner costs. The average cost per prisoner (holding one prisoner for the year) was £53,801, this was an increase of around 5% compared with the previous year.

Prisoners released in error

Between April 2024 and March 2025, 262 prisoners were released in error from prisons and courts in England and Wales.

This is the highest number on record and a 128% increase on those released in error in the year ending March 2024.

The number of prisoners released in error was around 0.5% of the 57,000 released from prison, having finished serving the custodial term of their sentence, in the year ending March 2025.

For more on this topic, see the Library article on Prisoners released in error.