Beyond capacity: Europe’s prison overcrowding challenge

This blog written by Idil Aydinoglu and is the first of three in a series examining trends in European prisons. It is produced in collaboration with EuroPris as part of Penal Reform International’s Global Prison Trends 2024 which was published with The Thailand Institute of Justice. The blog explores prison overcrowding – the data, impacts and key areas for reform. It draws on data collected from European prison administrations in 2024, among other sources. 

While European prisons may not evoke the stark imagery often associated with facilities in parts of Latin America or Asia—where detainees endure cramped and overcrowded conditions—several countries in the region still grapple with challenges related to prison overcrowding.  

The situation across Europe is far from uniform: while certain prison systems operate with surplus capacity, others struggle with overcrowded facilities, which pose significant operational and security challenges. These disparities complicate cross-country comparisons, particularly as methods for measuring prison capacity vary across the region. 

Variations in prison occupancy rates 

As of the end of January 2023, the average prison occupancy rate among Council of Europe (CoE) countries stood at 93.5 prisoners per 100 available spaces, according to the latest SPACE I. Although this represents a 2% increase from 2022, as a whole, European prisons are not overcrowded. However, numerous prison services regard an occupancy rate of 90% as the maximum operational threshold, aligning with the level recommended by the Council of Europe in its 2015 white paper on prison overcrowding. A closer look, however, reveals that prison occupancy rates differ markedly across the region, with some administrations reporting severe overcrowding (and sometimes in only some facilities), while others operate with surplus capacity and even seek to ‘rent out’ unused space.  

Data from eleven European countries reveal severe prison overcrowding, while an additional five report very high-density conditions, with occupancy rates just above 100%. Cyprus has the highest rate, with 166 prisoners per 100 available places, followed by Romania, France and Belgium, all exceeding 115. According to our research conducted in March 2024 in collaboration with EuroPris, which gathered information from 16 CoE member states, Slovenia’s prison population surged from 112% of capacity in mid-2023 to 133% by early 2024, while France and Croatia reported overcrowding levels of 123% and 113%, respectively. In contrast, Estonia reported an overall occupancy of just 54% in closed prisons, enabling a reduction in staffing levels.  Similar contrast can be seen in Luxembourg with 66%, and Spain with 75% occupancy rates. Facilities within the same jurisdiction can vary dramatically. In Catalonia, for instance, one prison operated at just 28% capacity, while another exceeded 100%, highlighting the challenges of managing prison populations even within a single administrative area. 

A close examination reveals that the accuracy of these figures is complicated by differing definitions and methods of measuring prison capacity across jurisdictions. While some jurisdictions calculate occupancy rates based on the “design capacity”—the number of people prisons were originally built to house—, others use “operational capacity,” which considers the number of people facilities can realistically accommodate, factoring in staff levels, available programmes, and other practical concerns. In addition, while some jurisdictions, such as Iceland, calculate occupancy rates based on the number of cells per individual, others, like France, base their calculations on the total available space per person. 

Research findings pointed to temporary expansion of capacity being another factor that needs to be considered to understand the full picture. For example, in Sweden, the inclusion of temporary living spaces has placed the overall occupancy rate at 99%, but without these spaces, it would increase to 113%. Similarly, Slovakian prisons, capacity calculations depend on the living space allocated per prisoner. There the prisons reported an official capacity of 87.75% with an accommodation area of 3.5 m² per 1 male and 4 m² per 1 female and child prisoners. This figure would increase to 96.69% if the minimum space requirement were applied to all prisoners the same, based on the standard set down by the European Committee for the Prevention of Torture (CPT) which is 4m². This exemplifies another variation in occupancy calculations, as seen in Czechia and Hungary, where different minimum living areas are required for various groups within prisons, sometimes falling below the minimum measurement set by the CPT. 

Underlying factors contributing to overcrowding 

Each member state experiencing high-density rates or overcrowding faces distinct challenges in ensuring sufficient space for people in prison. However, certain recurring factors can be identified, such as sharp increases in prison populations due to policy changes or insufficient infrastructure. 

A key factor contributing to overcrowding in some European countries can be traced to the significant increase in their prison populations. The prison population has been growing in Europe, especially following the discontinuation of post-COVID measures, making the rise in prison overcrowding unsurprising. For instance, Cyprus, Croatia and France, which already had overcrowded prisons, saw notable rises in their prison populations in 2023. However, this trend is not unique to these countries.  

Space II data on the non-custodial alternatives to imprisonment across Council of Europe member states points to a growing focus on non-custodial measures such as electronic monitoring, community service, and home detention. Notwithstanding net widening, 2023 recorded a 1% increase from 2022. The growth is insufficient and vastly differs across Europe.  Short sentences and the overuse of pre-trial detention are too often the norm. For example, a significant proportion of the prison population in the Netherlands are serving sentences of 6 months or less. Our 2022 research shows that a lack of awareness among justice professionals on real non-custodial sanctions and insufficient resources, which result in long waiting lists, limit their potential to reduce prison populations. This can be particularly problematic for marginalised communities. A 2023 European mapping research conducted by PRI in collaboration with EuroPris highlights how this factor disproportionately impacts certain groups, such as Roma, Traveller communities and foreign nationals without an address, who may culturally prefer not to have a permanent address. Justice professionals may be less inclined to implement non-custodial sentences in these cases due to the absence of a fixed address. 

The growing reliance on pre-trial detention, driven in part by political shifts towards more punitive approaches, is also placing increasing pressure on prison systems. As more individuals are detained before trial for a wider range of offences, the prison systems struggle to cope with rising numbers. Additionally, the imposition of longer sentences may exacerbate overcrowding in prisons. One significant consequence of such extended sentences is the ageing of the prison population. 

The impact of overcrowding 

Our 2024 research, conducted in collaboration with EuroPris, highlights the multifaceted and complex impacts of overcrowding. Overcrowding in affected prisons in the European region has far-reaching consequences, affecting both people detained in them, as well as staff. While issues like violence and staff burnout are not new, the intensity and severity of these challenges appear to be reaching unprecedented levels. Increased violence, both among people detained and against staff, is leading to burnout and reduced control within the facilities. This situation not only compromises the safety and well-being of everyone involved but also diminishes the prison system’s capacity for rehabilitation.  

In Spain, overcrowding has reportedly enabled criminal gangs to operate more freely within prisons, while in Slovenia, access to healthcare has been severely affected whereas the cancellation of 1,416 escorts has resulted in significant delays in court proceedings in 2023 due to the strain on resources. Slovenian prisons have also seen a rise in conflicts between prisoners, with recorded incidents increasing from 207 in 2020 to 314 in 2023. The Swedish Prison and Probation Service prioritises interpersonal contact as a fundamental right but faces persistent challenges due to overcrowding, limited staff, and space constraints, leading to inadequate efforts to reduce isolation. In 2023, prisoners were able to access less than half of their entitlement to interpersonal contact, while children in detention only received 57% of their allotted time. 

Overcrowding and an inadequate staff-to-prisoner ratio may limit access to essential rehabilitation programmes and meaningful activities is often limited, undermining efforts toward reintegration and positive change. In the Netherlands the occupancy rate exceeds the available staffing, prompting measures such as suspending the execution of sentences shorter than two months. The psychological impact of overcrowding is another significant concern. In Georgia, psychologists working in prisons reported that they are forced to focus on managing the everyday stress of prisoners rather than addressing longer-term rehabilitation needs. This reduces the effectiveness of efforts to reintegrate prisoners into society upon release, further exacerbating the cycle of recidivism.  

Efforts to address overcrowding 

While proposed solutions vary, there is a consensus that the issue cannot be tackled with a one-size-fits-all solution. Countries resort to various short, medium and long-term strategies to mitigate overcrowding, ranging from infrastructure development to policy reforms or early release schemes.  

Our research shows that construction of new (often bigger) facilities, renovation of existing ones, creation of temporary spaces continues to be pursued. In Croatia, modular container buildings are being constructed at overcrowded facilities, and annexes are being added to existing buildings to increase space. Sweden, for example, is planning to build larger institutions and is even considering the possibility of renting prison space abroad to cope with projected increases in its prison population. Authorities anticipate that prison numbers could increase by as much as 200% between 2023 and 2027 due to political shifts. 

In Slovenia, authorities have introduced measures such as the transfer of prisoners to less crowded prisons and implementing conditional release schemes. Upcoming legislation is also expected to help reduce the prison population by increasing the use of suspended sentences. Similarly, to tackle increasing prison population, Slovakia is working on extensive amendments in their legislation that is planned to reduce prison population and density. 

In England and Wales, an early release scheme when the new government was elected in 2024 sought to free up 5,500 spaces in total. As of September 2024, 1,700 prisoners had been released under the first round of the scheme. Austria has amended its Criminal Code to eliminate the use of default imprisonment when a fine cannot be paid, allowing individuals to opt for community service instead. In Sweden, authorities are re-evaluating security classifications to make better use of available space, while also streamlining staff recruitment and training to improve operational efficiency, especially considering anticipated political changes that could lead to a sharp increase in prison numbers over the next few years.  

Catalonia has adopted a strategy focusing on non-custodial measures, including restorative justice and reintegration programmes. These approaches aim to reduce recidivism by fostering rehabilitation and transitioning prisoners back into the community. This ‘openness strategy,’ launched in January 2024, seeks to bring more emphasis on the importance of diversion from imprisonment, which authorities believe will help to alleviate overcrowding while also addressing the root causes of criminal behaviour.  

In a nutshell… 

Prison overcrowding is a complex and multifaceted issue that presents significant challenges for European prison systems. While a minority of European countries are enjoying a ‘surplus capacity’, many prison systems are operating in a context of severe overcrowding, with wide-ranging impacts on both prisoners and staff.  

Although progress is being made in some places to address the drivers of overcrowding, any long-term solution will require sustained and coordinated efforts across all levels of the criminal justice system.