Prison Categories Explained

Prisons are categorised by security level to match the risk posed by different prisoners. Understanding these categories helps explain why prisoners are held where they are.

UK Prison Categories

In England and Wales, adult male prisoners are assigned a security category so they are held in the lowest suitable conditions that still manage the risks they present. HMPPS sets this out in its security categorisation policy framework: categorisation looks at escape risk, the harm that could follow an escape, and control issues inside custody.

Male prisons are organised into four categories:

• Category A: Highest security for prisoners whose escape would be highly dangerous to the public, the police, or national security. Establishments in this band include HMP Belmarsh, HMP Wakefield, and HMP Manchester (Strangeways). Within Category A, prisoners may be further classed as Standard, High, or Exceptional risk.

• Category B: High security for prisoners who do not need Category A conditions, but for whom escape must still be made very difficult. Category B sites include local prisons that receive people from court and training prisons. Examples include HMP Pentonville and HMP Wandsworth.

• Category C: Closed training and resettlement prisons for prisoners who cannot be trusted in open conditions but are not assessed as making a determined escape attempt. These prisons usually focus on education, work, and rehabilitation. Most sentenced adult men in England and Wales are held at Category C.

• Category D: Open prisons for prisoners who present a low risk and can reasonably be trusted in open conditions. Physical security is limited, and eligible prisoners may leave the establishment on licence for work, education, or other resettlement activity. Examples include HMP North Sea Camp and HMP Sudbury.

Browse Category A prisons · Category B prisons · Category C prisons · Category D (open) prisons. Lists of establishments live in the directory hubs; this guide explains the definitions only.

How Categorisation Works

New prisoners are assessed and categorised during reception and early sentence planning. Reviews continue during the sentence. As risk falls, prisoners may move to lower-security conditions; if risk rises, they can be moved the other way. Official HMPPS guidance on security categorisation is the authoritative source for how staff apply the rules.

Read the current HMPPS security categorisation policy framework on GOV.UK for the formal process. For a plain-language overview of Categories A–D, see the HMPPS prison jobs explainer.

Women's Prisons

Women's prisons in England and Wales are not formally categorised with the male Category A–D labels. They are generally described as closed or open. Restricted Status is used where a woman's escape would present a serious risk and designated secure accommodation is required. Most women's prisons operate at a level roughly comparable to closed conditions for men.

US Federal Security Levels

• Minimum: Camp-style facilities with limited or no fencing. Inmates are typically non-violent offenders serving shorter sentences. Work assignments often involve community service.

• Low: Double-fenced perimeters with dormitory housing. Greater staff supervision than minimum facilities.

• Medium: Strengthened perimeters with cell-type housing. Internal security measures are more rigorous.

• High: Highly secure with reinforced fencing and close staff supervision. Movement is highly controlled. USP Leavenworth is an example.

• Administrative/Supermax: The most restrictive, including ADX Florence. These facilities house inmates who pose the greatest threat to safety and security.

State Prison Systems

Each US state operates its own classification system, which may use different terminology. Most states use some variation of Minimum, Medium, Maximum, and Supermax designations, but the specific criteria for each level vary.