How Do You Get into a Category D Prison in the UK?

In the UK, Category D prisons — often known as open prisons — are intended for prisoners who are considered low risk and nearing the end of their sentence. But how exactly does someone end up in one? It’s not a case of simply asking to be moved. There’s a specific process, a set of criteria, and a review system that decides who qualifies for a place in a Cat D prison.

What Is a Category D Prison?

Category D prisons are designed to help prepare prisoners for life outside. They are the lowest security level in the UK prison system, meaning inmates are trusted enough to be held in conditions with minimal supervision and no physical barriers like walls or fences in some areas.

These prisons typically focus on rehabilitation, employment, and resettlement. Many prisoners here are allowed out on day release to work, attend courses, or visit family before returning in the evening — part of a structured release on temporary licence (ROTL).

Who Is Eligible for a Cat D Prison?

Not all prisoners are eligible for open conditions. Generally, the following criteria must be met:

The prisoner must be serving a sentence with a defined release date
They should pose a low risk to the public
There should be no strong history of escape or absconding
They must have demonstrated good behaviour inside prison
They are usually approaching the final stage of their sentence

Prisoners serving life sentences or long-term sentences may still be eligible, but only once they’ve passed several internal assessments, including Parole Board evaluations if necessary.

How the Re-Categorisation Process Works

Movement to a Category D prison usually follows a formal review. Every prisoner in a UK jail is assigned a security category — A, B, C or D — based on their risk level. Over time, if behaviour improves and risks reduce, they can be re-categorised to a lower level.

Here’s how the process usually unfolds:

The prisoner is reviewed by prison staff, including psychologists and security officers
A risk assessment is carried out (usually OASys – Offender Assessment System)
If approved, a transfer is requested and a space at a suitable Cat D prison is identified
The prisoner is transferred when appropriate, often with a resettlement plan in place

The review doesn't happen overnight — it’s based on time served, behaviour, rehabilitation progress, and overall risk level. Serious breaches of prison rules can delay or prevent progression to open conditions.

How Long Do You Need to Be in Prison Before Moving to Cat D?

There’s no fixed time, but generally, prisoners become eligible for review after serving half their sentence or once they are within a certain number of months from their release date. For some, that could be within two years of release; for others, especially those on longer sentences, the timeframe may be longer.

Life-sentenced prisoners may only be considered after a minimum tariff is served and if deemed safe by the Parole Board.

Why Would Someone Be Refused Open Conditions?

There are several reasons a prisoner might not be approved for a move to Cat D, such as:

Recent disciplinary action or rule-breaking
Ongoing investigations or intelligence suggesting risk
Lack of a clear resettlement plan
Concerns about absconding or failure to return from ROTL

If refused, the prisoner can usually reapply after a certain period — often six to twelve