Prison Categories Explained: Category A, B, C, D and Open

In shortPrisoners are held in the lowest security conditions necessary to manage their risk: A to D for adult men, Closed or Open for women and young offenders.

UK prison categories in England and Wales come from the Security Categorisation Policy Framework, which says prisoners are categorised according to the risk they present to security, safety and public protection and must be held in a prison providing levels of security appropriate to managing identified risks.

The aim, in the framework's words, is that prisoners are held in the lowest security conditions necessary to manage their identified risk.

For adult men there are four categories: Category A at the top, then B, C and D. Women and young offenders (18 to 20 in YOIs) are categorised as Closed or Open, because closed conditions are not subdivided for them.

'Open' prisons have minimal perimeter and physical security and are for those specifically assessed as suitable for conditions of low security. These are England and Wales rules. Scotland and Northern Ireland have their own systems, which this guide does not cover. For a list of which prisons are which, see our UK prisons list.

In shortCategory A is defined by how dangerous an escape would be, not how likely; women and young people in the equivalent position are Restricted Status.

PSI 09/2015 defines a Category A prisoner as one whose escape would be highly dangerous to the public, or the police or the security of the State, and for whom the aim must be to make escape impossible.

It stresses that the definition is concerned with how dangerous the prisoner would be if they did escape, not how likely they are to escape.

The DDC High Security is responsible for categorising and allocating Category A prisoners.

Category A is itself subdivided in two ways.

By status

Potential Category A (an interim decision while a final one is awaited), Provisional Category A (the decision is made and, if held outside the high security estate, they are moved to a High Security prison) or Confirmed Category A (held in a High Security prison, deemed Category A at first formal review).

By escape risk

Standard, High or Exceptional Escape Risk, with the last reserved for cases where credible information suggests an escape attempt is being planned.

Restricted Status

Women, young people and young adults whose escape would present a serious risk to the public are classed Restricted Status instead, held in designated secure accommodation, and are treated as Category A prisoners whenever they leave their establishment.

• There is no list of 'Category A prisons'.
• HMPPS ratings give five prisons the High Security functional group (Frankland, Full Sutton, Long Lartin, Wakefield, Whitemoor), but this is a role label.

In shortClosed prisons for men are Category C (standard security) or Category B (additional security for greater risk of escape or disorder).

Closed prisons have a secure perimeter and a range of internal security measures. For adult men the framework divides closed conditions into Category C prisons and Category B prisons. This also explains why some prisons in the HMPPS functional-group system carry 'Category B' as a label, such as Dovegate or Garth.

Placement is not purely about category. Allocation also looks at sentence, offending behaviour programmes, health and available places, and the framework sets out the assessment steps. We cover the prisons labelled Category B and C in the list at prisons by category and the explanatory HMPPS structure guide.

In shortCategory D and Open are for those assessed as low risk; since April 2025 determinate-sentence prisoners become eligible at 5 years from earliest release, up from 3.

Category D (adult men) and Open (women and young offenders) are for those assessed as presenting a low risk, or whose previously identified risk factors are now assessed as manageable in low security conditions. They are held in open prisons, which have minimal perimeter and physical security features.

HMPPS gives 13 establishments in England and Wales the Open functional group: HMP & YOI Hatfield, HMP & YOI Hollesley Bay, HMP & YOI Prescoed, HMP & YOI Thorn Cross, HMP Ford, HMP Haverigg, HMP Kirkham, HMP Kirklevington Grange, HMP Leyhill, HMP North Sea Camp, HMP Spring Hill, HMP Standford Hill and HMP Sudbury.

Women's open prisons are Askham Grange and East Sutton Park, which HMPPS groups under Female, and Castle Huntly is Scotland's only open prison. See open prisons explained.

• Those serving indeterminate sentences are not assessed for open conditions by the prison itself.
• The same update strengthened the requirement to review OASys before a prisoner is considered for Category D or Open and to inform Victim Liaison Officers.

In shortClosed conditions are not subdivided for women or young offenders: they are Closed or Open, with no Category B or C.

The framework states there is no subdivision of closed conditions for young offenders or female prisoners.

HMPPS groups 12 women's establishments under the Female functional group (Askham Grange, Bronzefield, Downview, Drake Hall, East Sutton Park, Eastwood Park, Foston Hall, Low Newton, New Hall, Peterborough, Styal and Send), where Peterborough's female side appears as Female / Reception.

The female population on 28 September 2026 was 3,407 against a useable capacity of 3,718. Under-18s are held in the Youth Custody Service estate, which has separate arrangements. See women's prisons in the UK and the youth custody estate.

In shortThe initial assessment is due within 10 working days of sentencing, then reviews every 12 months, or every 6 months once under 3 years remain (determinate sentences).

The initial security categorisation assessment must be completed by the Prison Offender Manager within 10 working days of sentencing, so the prisoner can be moved to an appropriate prison quickly. Because it is done so soon after conviction, the information available can be limited, and the framework says the decision must reflect the individual circumstances.

Categorisation is then reviewed. A prisoner serving a determinate sentence in closed conditions must be reviewed every 12 months until they have less than 3 years left to serve to earliest release; once under 3 years the review is every 6 months.

For indeterminate sentences reviews normally align with sentence planning reviews. A non-routine review must take place whenever circumstances change in a way that affects security risk, for example an assault in custody or new information about links to serious organised crime.

1. Sentence passed. The prisoner is in custody awaiting categorisation and allocation.
2. Within 10 working days the Prison Offender Manager completes the initial categorisation assessment.
3. The prisoner is allocated to a prison providing the appropriate security level.
4. Routine reviews follow every 12 months, or every 6 months once less than 3 years remain to earliest release (determinate sentences).
5. A non-routine review takes place if risk changes or new information emerges.
6. Open conditions are considered when determinate prisoners come within 5 years of earliest release (PED or CRD).

In shortA functional group is HMPPS's role label for a prison; HMPPS does not publish a plain-English definition of each group in the ratings tables we opened.

Alongside prisoner categories, HMPPS puts every rated prison into a functional group. The groups used in the 2025/26 ratings are Reception, Category C Trainer, Category C Trainer/Resettlement, Category C Resettlement, Category C Foreign National, Category B, High Security, Open and Female.

In our dataset of 123 England and Wales establishments the counts are in the table below.

HMPPS does not publish a plain-English definition of each group in the ratings tables we opened, so we describe them only where official GOV.UK or inspectorate wording exists for individual prisons.

For example, the wording gives Belmarsh as high security with the A category, Birmingham as Category B reception, Dovegate as Category B training, Erlestoke and Featherstone as Category C training and resettlement, and Morton Hall as Category C resettlement for foreign national men. Those are the prison's own role descriptions, not a general rule.

In shortThe functional group describes the establishment's role; a prisoner's category is a decision about him.

Consider HMP Birmingham. HMPPS gives it the Reception functional group, while its official description gives the role as Category B reception. A man categorised Category B could be held there, but the label alone does not tell you that. The label describes the establishment's role. The prisoner's category is a decision about him.

Now consider HMP Garth, grouped as Category B in the ratings and described officially as high security. It sits in the Long Term and High Security estate, but it is not in the five-prison High Security functional group (Frankland, Full Sutton, Long Lartin, Wakefield and Whitemoor).

Confirmed Category A prisoners are held in High Security prisons, as PSI 09/2015 says; which establishments count for that purpose is a matter for the HMPPS High Security directorate.

• Use the functional group to understand what a prison does.
• Use the framework to understand prisoner categories.
• Never infer one from the other without reading the prison's own page.

In shortWe have not found a source that links prisoner category to officer pay, shift patterns or duties.

Be careful here: the published framework is about prisoner assessment, not staff working conditions, and we have not found a source that links prisoner category to officer pay, shift patterns or duties.

Pay for public-sector officers varies by pay zone (national, outer London and inner London), contract hours and any market supplement, not by the category of the prison. Our prison officer pay bands and market supplements guide set out the figures.

• Prison Offender Managers complete the assessments and security departments supply intelligence.
• Non-routine reviews must follow events such as an assault in custody (the framework).
• For Category A and Restricted Status prisoners, escorts must meet Category A standards, and PSI 09/2015 requires the holding establishment to provide a minimum of two officers for certain escorts.