There has been a dramatic deterioration in standards across prisons since 2009/10. The sharp rise in deaths, violence, self-harm, poor behaviour and drug use – as well as a drop-off in efforts to rehabilitate prisoners – can all be linked to the cuts in government spending on prisons, and a fall in the number of prison officers between 2009/10 and 2015/16.

These disappointing, and worrying, results have prompted the government to act. However, despite starting to reverse the reductions in spending on prisons and the number of prison officers, both remain below 2009/10 levels and prison performance continues to deteriorate.

The size of the prison population is due to fall in future years, but spending is planned to fall faster. The gap between spending and demand in 2023/24 will be even larger if the Johnson government implements its proposals on police numbers, Crown Prosecution Service spending and sentencing reform.

There are 117 prisons in England and Wales. Her Majesty’s Prison and Probation Service (HMPPS) runs most of these (104) while three private companies operate 13: G4S and Sodexo manage four prisons each, and Serco manages five. Private prisons are newer than those operated by the public sector and tend to be larger.

This chapter covers all of these prisons, though less data on private prisons is available, particularly with regards to their workforce.

Spending on prisons is 14% lower in real terms than in 2009/10

Change in spending on prisons in England and Wales since 2009/10 (real terms)

Government spending on prisons has fallen considerably since 2009/10. Recent investment has only just begun to reverse this trend. In 2017/18, the government spent £3.2 billion (bn) on prisons. On a like-for-like basis,* taking into account economy-wide inflation, spending was 14% lower than eight years earlier, having reached its lowest point in 2015/16, when it was 19% below 2009/10 levels in real terms.[1]

The increase in spending in 2016/17 and 2017/18 followed an announcement in the 2016 autumn statement of £291 million (m) of additional funding over three years to recruit 2,500 additional prison officers to improve prison safety.[2] In the 2018 budget, the government committed a further £30m for 2018/19 to enhance prison security.[3]

On top of additional funding to increase prison officer numbers and boost security, the Cameron government announced £1.3bn more capital funding in the 2015 autumn statement to invest in reforming and modernising the prison estate, and committed in 2016 to build 10,000 new prison places.[4] The Johnson government has since announced that up to £2.5bn will be spent, re-committing to creating 10,000 new prison places in addition to the two new prisons already announced at Glen Parva and Wellingborough.[5] Unlike the funding mentioned above, this is intended primarily to boost prison capacity and will not target pressures in existing prisons.

* In some years, there are small adjustments in recorded spending due to changes in what is accounted for in Ministry of Justice spending on prisons. In these cases, we have adjusted previous years’ prison spending numbers such that annual percentage changes in prison spending are unaffected by these adjustments and are always based on a like-for-like comparison.

Prisoner numbers have fallen – but demands on prisons have risen overall

The prison population in England and Wales

Note: Figures are from 30 June of each year.

The total prison population is largely unchanged from 2009/10 levels, but the demands on prisons and their staff appear to have become more complicated over the 10-year period.

The proportion of the prison population accounted for by men and women has changed dramatically over the years. In 1900, 17% were women. This fell to a low of 2% in the late 1960s but then rose again slowly, reaching 6% in 2001, before falling slightly to 5% in 2007; since then the population mix has remained steady.[6]

As of June 2019, the prison population in England and Wales was 82,710. This was the lowest population at this time of the year of the past 10 years. The prison population peaked at 88,167 in November 2011.[7] While the number of prisoners has fallen slightly over the past two years, the evidence suggests that the overall needs of the prison population have increased, with more older prisoners, and a greater prevalence of drugs, alcohol and weapons in prisons.

Between June 2011 and June 2019, the number of prisoners aged 60 and over rose by 69%, from 3,015 to 5,082. Since June 2016, the first year for which figures are available, there has also been a particularly sharp increase in the number of prisoners aged 70 and over (25%). At the same time, the number of young prisoners has declined, with 27% fewer prisoners aged under 30 in 2019 than in 2011.[8]

Older prisoners can put additional strain on prisons. This age group has higher levels of illness and many will need additional support to access activities or outside space. Prisons may need to provide physical adaptations and specialist training for staff. In a joint report, Her Majesty’s Inspectorate of Prisons (HMIP) and the Care Quality Commission found gaps in the provision of services for older prisoners, wide variations across the prison estate and little evidence that prisons were adequately prepared for the continued growth in the older prison population.[9]

Increased use of drugs has made prisons more challenging to manage. According to the Ministry of Justice (MoJ), “the prisons with the highest rates of positive random drug tests are the prisons that are the least stable”.[10] Unfortunately, the percentage  of drugs tests with positive results for ‘traditional drugs’ such as cannabis and opiates rose from a low of 7.0% in 2011/12 to 10.0% in 2018/19, though this is down from a peak of 10.6% in 2017/18.

Higher apparent use of traditional drugs has been accompanied by an influx of synthetically produced drugs collectively known as ‘psychoactive substances’, which appear to be at least as prevalent as traditional drugs. In 2016, HMPPS became the first prison service in the world to introduce mandatory tests for these drugs.[11] The two years of data available show that psychoactive substances are used widely. In 2017/18, 21.3% of inmates tested positive for either psychoactive substances or more traditional drugs. This fell to 17.7% in 2018/19.[12]

However, HMIP found that in 2017/18 the mandatory drug testing programme was not running effectively in 18 of the 39 men’s prisons it inspected (46% of those prisons) – mainly due to staff shortages.[13] Official figures may therefore underestimate the true scale of drug use in prisons.

The quantity of drugs and drug equipment found in prisons has increased over the past few years. Between 2016/17, the first year for which figures are available, and 2018/19, discoveries of drugs and drug equipment increased by 73% and 157% respectively. There has also been a large rise in the number of other illicit items found. Most notably, finds of alcohol and distilling equipment rose by 100% and 125% respectively between 2016/17 and 2018/19, while 105% more weapons were found over the same period.[14]

It is possible that these figures reflect better detection rather than increased prevalence. For example, since 2016/17, HMPPS has trained more than 300 drug dogs to detect psychoactive substances, which will have increased the frequency with which these drugs are found. However, it is likely that at least some of the rise in finds reflects increased availability of these items in prisons, with the government’s prison drugs strategy acknowledging that the “scale of the problem is significant and has become more challenging in recent years”.[15] Increased availability of drugs, alcohol and weapons will increase the complexity of supervising the prison population.

Fewer, larger prisons

The number of prisons in England and Wales fell from 137 in 2009/10 to 117 in 2018/19. But, despite more prisons closing or merging than opening, the total capacity of the prison system has stayed broadly the same because the new prisons that have opened are larger than the ones they have replaced and new accommodation blocks have been built at existing prisons. The total operational capacity of prisons has fallen only slightly, from 87,090 in March 2011 to 86,473 in March 2019.

Government plans to increase prison capacity have proceeded more slowly than originally intended. Berwyn prison, which opened in 2017, is the only brand-new prison that has been initiated and built since 2009/10. Two years later, the prison was still 40% empty because of delays to building work, including the completion of workshops, and currently remains around a third below its intended capacity of 2,100 places.[16]

Under the Prison Estate Transformation Programme (PETP), the Cameron government committed to create 10,000 new prison places. The programme included two new prisons – in Port Talbot and Full Sutton – and the rebuilding of existing prisons in Glen Parva, Hindley, Rochester and Wellingborough.[17] The first to be built as part of this programme was the former HMP Wellingborough.[18] Construction of the new prison commenced in May 2019 and it is due to open in 2021. The former HMP Glen Parva has also been demolished in preparation for construction in summer 2020, with work due to be completed by summer 2023.

It was decided in July 2017 that the closures of both Hindley and Rochester prisons should be postponed. Cells at these sites are to be kept in use for now, as part of forward-planning for the estate. In September 2019, planning permission was granted to build the new 1,017-place prison at Full Sutton.*

The House of Commons Justice Committee has concluded that while the PETP has made some progress, “sites for new prisons have proven difficult to obtain, older and decrepit prisons have been forced to remain open owing to population pressures and receipts from the sale of existing sites do not cover the cost of building new prisons.”[19]

* Plans for the new prison in Port Talbot have been scrapped following objections from the local community.

Staff numbers in public prisons have increased, following deep cuts

Change in the total number of core operational staff (bands 3–5) in public prisons since 2009/10

Note: All staff numbers are full-time equivalent, as of 31 March.

The analysis in this section is focused on the workforce in publicly run prisons because the MoJ does not collect workforce data from private prison providers. Given the increase in violence across the prison estate, we believe that the department should start to collect and publish this data immediately to assess whether private prisons have safe staffing levels.

In 2017/18, payroll accounted for 39% of spending on prisons, down from 47% in 2012/13 (the first year for which comparable figures are available). Total spending on payroll fell by 17% in real terms between 2012/13 and 2016/17, before growing by 5% in 2017/18.[20]

Between March 2017 and March 2019, the number of full-time-equivalent prison officers rose by 4,228 (23%). As a result, at the end of the 2018/19 financial year, there were 22,630 band 3–5 prison officers in public prisons in England and Wales. The government has, therefore, comfortably exceeded its target, set three years ago, to recruit 2,500 additional prison officers, though it has only partially reversed the large decline – of 27%, or 6,609 prison officers – that occurred between 2009/10 and 2014/15.

While prison officer numbers are nearly at the same level as they were seven years ago, the workforce is now much less experienced. In March 2019, 50% of prison officers had less than five years’ experience, compared with 22% in March 2010 and just 6% in March 2014. Just under half (46%) had at least 10 years’ experience or more, down from 56% in 2010 and a high of 66% in 2014.[21]

This change in staff composition is due to a large number of prison officers leaving each year, many of whom had been with the service for more than five years. More than 1,500 prison officers left through voluntary early departure schemes between March 2013 and March 2014, with 720 leaving in September 2013 alone. The average length of service of staff who left through these schemes ranged from 17.2 years to 24.5 years in each month over this period during which there were departures.[22]

The loss of experienced staff can damage the quality of support and supervision within prisons. HMIP noted in its 2018/19 annual report that “some prisons had a large proportion of new and very inexperienced staff who sometimes struggled to challenge poor prisoner behaviour” and cited staff inexperience as a contributing factor to the poor performance of HMP Birmingham.[23]

Standards in prisons have declined on almost all measures

On every key measure, prison performance has declined in recent years. Prisoner misbehaviour, violence and self-harm have all become more prevalent, while rehabilitative activities have become less widely available.

Only on their most basic responsibility – keeping prisoners in custody – have prisons maintained good performance, with no more than two escapes* a year between 2009/10 and 2018/19, apart from in 2016/17 when four prisoners escaped. Similarly, the number of prisoners who absconded from open prisons fell from 269 in 2009/10 to 120 in 2018/19, with a low of 86 in 2016/17.[24]

* Where a prisoner has to physically overcome some restraint or barrier to go out of the control of the staff.

Incidents of poor prisoner behaviour have increased

Change in the number of incidents of protesting behaviour in prisons in England and Wales since 2012/13

There has been a massive rise in incidents of poor prisoner conduct over the past six years. Incidents of ‘protesting behaviour’ are categorised in four ways:

• barricades/prevention of access: prisoners use a physical barrier to deny access to all or part of a prison

• hostage incidents: prisoners hold people against their will

• concerted indiscipline: two or more prisoners refuse to comply with instructions/rules

• incidents at height: any incidents taking place above or below ground level,* including climbing over bars, on the roof or on netting.

Between 2012/13 – the earliest year for which there are consistent figures – and 2018/19, there was a more than fivefold increase in the total number of incidents per year, from 1,366 to 7,781. The majority of these (and the fastest-growing category) were incidents at height. There were 5,583 such incidents in 2018/19, an increase of 657% since 2012/13. The number of barricades – the second-largest category – also grew consistently over this period, from 475 to 1,749, a rise of 268%.

Incidents of hostage taking and concerted indiscipline have also grown but are both below their peak. Hostage incidents rose from 54 in 2012/13 to 129 in 2015/16, before falling to 98 in 2018/19 – an overall rise of 81% over the period. Incidents of concerted indiscipline rose from 99 in 2012/13 to a high of 380 in 2016/17. This fell to 339 in 2017/18 before rising again to 351 in 2018/19 – a total increase of 255% over the past seven years.[25]

Prisoners involved in these sorts of incidents, plus those alleged to have committed other (substantially more common) offences in prison, are put through a process known as adjudication, where the allegations are assessed.** Alongside the large increase in incidents, there has been an increase in the number of adjudications. Between 2011 and 2018, the number rose by 71%, from 119,678 to 204,715.

Proven adjudications have also increased, but only by 52% over the same period. As a result, the share of allegations that are proven has fallen from 73% to 65%. The reason for this drop is unclear but the MoJ has stated that it “may reflect a change in the types of offences adjudicated against”.[26]

* Incidents below ground level would include those that take place in the basement. They would not include tunnelling, as this would be classed as an escape or attempted escape.

** The recording of incidents of protesting behaviour is not dependent on whether the allegation is upheld at a subsequent adjudication. Rather, prison officers record incidents when they judge that it is likely, beyond reasonable doubt, that the incident occurred.

Prison violence continues to worsen and prisoners are self-harming more often

Number of assaults in prisons in England and Wales

In August 2018, Rory Stewart, then prisons minister, pledged that he would resign if levels of violence and drug use did not decline in 10 selected prisons over the following year. The pledge was supported by an investment of £10m.[27] Stewart did not stay in post long enough to realise this pledge – he was appointed international development secretary in May 2019 and then stood down from the government in July 2019.

He would not have had to resign had he remained prisons minister: across the 10 prisons there was a 15% decline in the number of assaults per 1,000 prisoners compared with a 5% decline in comparable category B and C prisons.[28] Concerns have been raised, however, that this has been achieved by diverting resources from other prisons[29] and violence levels across the wider prison estate remain very high.

Prisoner-on-prisoner assaults more than doubled from 11,892 in 2009/10 to 24,541 in 2018/19, with serious assaults rising even more quickly – from 1,087 to 3,017 over the same period – though they fell slightly in the past year. Assaults on staff have grown at an even faster rate, with 10,311 in 2018/19, more than three times the number in 2009/10.

There has also been an increase in the number of self-harm incidents in prisons. These rose from 24,964 in 2009/10 to 57,968 in 2018/19 – an increase of 132%. In the past year alone there has been a rise of 24%. Self-harm incidents are far higher in women’s prisons, with 2,828 for every 1,000 female prisoners, compared with 596 for every 1,000 male prisoners. The rate of self-harm incidents in women’s prisons fell from 2,624 per 1,000 prisoners in 2009/10 to 1,552 per 1,000 prisoners in 2012/13, before rising again to the current level.

In 2018/19, roughly three out of every 10 female prisoners self-harmed at least once.[30]

Self-inflicted deaths in prison fell from a peak of 108 in the 12 months to June 2016, to 86 in the 12 months to June 2019. However, the number rose slightly in the past year and is still 46% higher than the figure recorded in 2009/10.[31]

According to analysis by the MoJ, the figures for both assaults and self-harm are likely to be underestimates, with around 10% of assaults and 11% of self-harm incidents going unreported in the 2017/18 official statistics.[32]

Prisoners have less access to rehabilitative activity

If prisoners spend more time in their cells, they will spend less time engaged in retraining and education. But the evidence suggests that this is exactly what is happening. This is at odds with HMPPS’s mission statement to “reduce re-offending by delivering the punishment and orders of the courts and supporting rehabilitation by helping offenders to reform their lives”.[33]

Information on the extent to which prisons are supporting rehabilitation comes largely from inspection reports, rather than comprehensive data on all prisons. Although conclusions must therefore be more tentative, it does appear that prisoners now have less access to rehabilitative activities than they did in the past.

HMIP provides inspected prisons with a grade for purposeful activity – the extent to which “prisoners are able, and expected, to engage in activity that is likely to benefit them”. In 2018/19, 42% of inspected prisons were considered ‘good’ or ‘reasonably good’, with 26% marked as ‘poor’. Figures are not directly comparable from year to year because the survey takes place only in inspected prisons, but the proportion of prisons being graded as ‘good’ or ‘reasonably good’ in 2018/19 was the second lowest – and the proportion marked as ‘poor’ was the highest – since 2010/11 (when the figures were 69% and 8% respectively).

Extra time spent in cells has further consequences, with prisoners having reduced access to exercise, and resettlement and healthcare services. It can also lead to greater boredom, frustration and use of drugs.[34] In its 2018/19 survey, HMIP found that only 10% of prisoners were unlocked for the recommended 10 hours a day and 24% spent less than two hours a day out of their cells. As above, these figures are not directly comparable to previous years, but it is notable that these are the worst figures since 2010/11.

Number of offenders starting and completing accredited programmes while in custody

With prisoners spending more time in their cells, it is not surprising that fewer are starting and completing accredited courses and qualifications that may support them on their release from prison.

The number of prisoners starting accredited programmes to reduce domestic violence, offending, sexual offending and violence fell by 36% between 2009/10 and 2017/18 (from 9,362 to 6,001).* The methodology for calculating completions of accredited programmes has only been consistent since 2014/15; since then completions have fallen by 23%.[35]

Similarly, there has been a decline in the number of prisoners gaining academic qualifications. In 2017/18, 40% fewer prisoners achieved a level 1 or 2 (pre-GCSE and GCSE-level) qualification in Maths than in 2010/11 (6,520 versus 10,950) and 47% fewer achieved a level 1 or 2 qualification in English (6,260 versus 11,760).[36]

* These figures exclude substance misuse programmes as responsibility for these transferred from HMPPS to the NHS in 2011.

Have prisons become more efficient – and if so, can that be maintained?

The past decade has seen a major decline in the quality of the prison service. While this might seem an inevitable outcome of budgetary cuts, the cuts to the MoJ budget proposed in the 2010 spending review were originally due to be achieved partly through sentencing reform and a subsequently smaller prison population. But that never happened. Following criticism of the plans to increase sentencing discounts for early guilty pleas, then Prime Minister David Cameron said in 2011 that “money that would have been saved through this proposal will be saved through greater efficiency in other parts of the Ministry of Justice budget”.[37]*

In practice, the government cut prison spending by holding down pay and cutting staff numbers up to 2016/17. Pay was frozen between 2011/12 and 2012/13, and then capped at 1% a year until 2016/17. As a result, real-terms spending on payroll (which now makes up 39% of total prisons spending) fell by 22% between 2012/13 and 2016/17.

Prisoner numbers rose by 2% between June 2009 and June 2016, but the number of prison officers fell steeply (by 26%). The sharpest fall was in 2013/14, when prison officer numbers were cut by 15%. However, it was inefficient to allow so many experienced prison officers to leave through voluntary early departure schemes in 2013/14, as new staff had to be recruited and the loss of experience likely played a role in declining performance.

Widespread evidence of worsening standards suggests that there were no efficiency savings in prisons alongside the cuts. The government acknowledged in the 2016 autumn statement and 2018 budget that prisons required more money to improve standards.[38]

Since 2015/16, spending on prisons has increased but prisoner numbers have fallen, and standards have continued to worsen. On the face of it, this suggests there has been a marked decline in the productivity and efficiency of public prisons over recent years. It is harder to reach firm conclusions about what has happened in privately operated prisons, as the MoJ does not collect information on the number and type of staff in private prisons.

It is possible that it will take time for standards in prisons to recover following the increase in staff numbers. A large number of inexperienced officers have been recruited over the past three years and it may take time for them to manage prisoners effectively.

However, retention has become increasingly difficult. If this continues, the prison service could face an ongoing challenge to train large numbers of new officers each year and to manage the prison population with a relatively inexperienced workforce.

There has been a notable change in the reasons why prison officers leave their jobs. In 2009/10, 34% of staff left due to retirement and 34% resigned. In 2018/19, just 12% of leaving officers retired, while 62% resigned.**[39] The rising number of resignations suggests that the workforce are increasingly unhappy. There has been a particularly large increase in the number of new staff quitting. In 2009/10, just 150 officers with less than two years’ experience left the service. In 2018/19, 1,428 – nearly 10 times as many – did so.[40] For the past two years, the government has been able to recruit more staff than have left, but it is inefficient to recruit and train staff only for them to leave within two years.

The government may also be storing up problems for the future by using its capital budget to meet demand pressures. In both 2017/18 and 2018/19, the MoJ, with HM Treasury agreement, redirected money from its capital budget towards day-to-day spending in order to manage wider pressures driven by increased demand on the justice system and lower-than-anticipated fee income. In 2017/18, £235m was moved[41] and in 2018/19 a further £150m was transferred across.

However, it is unclear how much of this money was used for prisons specifically, as opposed to other areas of MoJ spending, such as courts.[42]

The government has set out plans for saving £16m a year from 2019/20 by reducing the overtime bill and other workforce reforms. It intends to save a further £7m a year by reducing use of agency staff and of ‘detached duty’, whereby staff from one prison are sent to another prison to ease a staff shortage.[43]

There is limited information available on non-staff prison spending. Small reform programmes such as the digital prison pilots[44] and ‘send money to someone in prison’ online service[45] may create efficiencies but larger programmes have run into difficulties. Delays to the PETP mean that planned savings – by replacing older prisons that are more expensive to run with newer, more efficient prisons – have not been fully realised. The collapse of Carillion has also required the MoJ to spend an additional £15m a year on the maintenance contracts that the firm previously managed.[46]

Any savings that can be found are unlikely to offset the additional spending on prisons now that the size of the workforce is growing and the pay cap has been eased. In the past two years, the number of prisons officers increased by 23%. Staff received a 1.7% pay rise in 2017/18, a 2.75% increase in 2018/19 and a 2.2% increase for 2019/20 (with a 3% rise for more junior officers).[47]

Considering the major decline in the quality of prisons – with increased prisoner protests, adjudications, violence and self-harm, and reduced rehabilitative activity – it is clear that the service has become less efficient. Attempts to improve quality through the recruitment of additional staff in the past two years have had no impact so far. But, earlier staff reductions took a while to show up in the data and it may be that reversing these cuts will have a similar ‘lagged’ effect.

* For a full explanation, see Thornton D, Pearson J and Andrews E, Managing with Less: The 2015 Spending Review, Institute for Government, 2015, retrieved 14 October 2019, files/publications/Managing_With_Less_WEB_0.pdf

** The other categories are voluntary exit, death, dismissal and other (which includes transfers to other parts of the public sector).

Have efficiencies been enough to meet demand?

Prisons have not made genuine efficiencies since 2009/10 but demand has grown. The total number of prisoners has fallen in recent years and levels of overcrowding were relatively steady from 2009/10 until 2017/18, with between 23.9% and 25.5% of prisoners being held in crowded accommodation. In 2018/19, the proportion fell to 22.5%, the lowest level since 2002.[48] However, the evidence suggests that overall demand has grown, with an ageing prison population and increased availability of weapons, alcohol and drugs in prisons.

Prisons have also faced a sizeable funding gap. In evidence to the House of Commons Justice Committee in 2018, Mike Driver, chief financial officer at the MoJ, said that the department faced a funding gap of £1.2bn across 2018/19 and 2019/20.[49] Following a renegotiation with the Treasury before 2019/20 budgets were agreed, the gap has narrowed,[50] but this shows that the department has not been able to meet demand through efficiencies.

In recent years, the government has failed to sufficiently maintain the prison estate, contributing to a growing maintenance backlog. The size of the current backlog for major works to improve the fabric of the prison estate stands at around £900m.[51] This is up from £716m in August 2018. In 2018/19, MoJ Estates only had funding of £90m to deliver major maintenance/investment schemes.[52]

How will demand for prisons change?

Government spending on prisons is due to fall faster than the number of prisoners. However, the prison population may in fact grow due to government policy and spending decisions.

The MoJ estimates that the number of prisoners will fall by 1.3% between 2018/19 and 2023/24.* On the face of it, this suggests that the government could reduce real-terms spending on prisons by 1.3% (or £41m a year by 2023/24) while still maintaining their current scope and quality.

The level of prison spending implied by current government plans would fall slightly short of these demands – that is, assuming that prison spending rises in line with the MoJ’s budget between 2018/19 and 2020/21, and then falls at the same average rate as other unprotected areas after 2020/21. Current plans imply prison spending being £50m (or 1.6%) lower in 2023/24 than in 2018/19, which would reduce funding available per prisoner by 0.3%.

Projected spending and demand for prisons


Projected increase in demand by 2023/24 -1.3%
Spending scenario Current government policy Recent trajectory Meet demand
Change in real-terms spending by 2023/24 -1.6% 18.7% -1.3%
Spending in 2023/24 (2018/19 prices) £3.1bn £3.8bn £3.1bn
Impact on unprotected government spending (2018/19 prices) -£0.6bn
Projected gap (2018/19 prices) -£0.6bn

Source: Institute for Government calculations, see Chapter 13, Methodology. 

However, this projection of the gap between spending and demand may be overoptimistic. The Johnson government’s plans to increase the number of police officers (see Police, in this chapter), increase funding for the Crown Prosecution Service[53] and review sentencing policy[54] could push up the size of the prison population and thus the spending required to maintain current standards.

Government spending would also need to increase faster than growth in the prison population if the government wants to meet its ambition – set out in the MoJ single departmental plan – to reduce prison violence and self-harm.[55] The government’s 10 Prisons Project, where Rory Stewart pledged to reduce levels of violence and drug use in 10 selected prisons between August 2018 and August 2019, showed that boosting the resources available to prisons can reduce levels of violence.

But it may take a few years for the performance of the wider prison system to benefit from increased spending and growing numbers of prison officers.

Since the 2015 spending review, spending on prisons has grown by an average of 3.5% in real terms each year. If this rate of growth were to continue, prisons spending would be 18.7% (£600m a year) higher by 2023/24 than it was in 2018/19 – implying that the government would have to either increase its overall spending plans or find £600m cuts elsewhere.

* See Chapter 13, Methodology.