HMP/YOI Isis had stopped separating young men on its wings according to their London gang affiliations, and inspectors found the bold change had started to pay off. The prison now ran a better regime, and two of its four inspection grades had risen.
HM Inspectorate of Prisons published its report on Isis in March 2026. Inspectors finished their fieldwork in December 2025.
Isis, in Thamesmead in south-east London, is a category C training and resettlement prison for young men aged 18 to 27. It held 577 men at the time of the inspection, against an operational capacity of 628.
The end of postcode-led placement
At the previous inspection, staff kept men from rival London gangs on different wings so that those in conflict did not mix. Inspectors said this approach produced a highly restricted regime. In the words of the report, it created “a highly restricted regime which fed, rather than addressed, the cycle of violence and retribution in which so many prisoners were trapped”.
The governor had since introduced what the prison called the Peace strategy. It ended automatic placement by postcode. It also created a Peace spur for men who wanted to serve their sentences away from gang conflict. Men on that spur received more time out of cell and more enrichment activities.
Some men on the Peace spur told inspectors they did not always get their entitlements and that their regime sometimes faced restrictions. Inspectors warned that leaders must stop this becoming a regular occurrence, or the reward for good behaviour would lose its value.
The prison also opened a Growth spur for men who could not live alongside those they had conflict with. The regime there remained very restricted. Even so, a motivated staff team used a range of interventions to help men move back to main wings. Two older prisoners serving life sentences supported this work through the Men of Purpose initiative.
Violence rose sharply in the months after the change, especially assaults on staff. By the time of the inspection, incidents had fallen considerably as prisoners began to accept the new approach. A further Peace wing was due to open shortly after the inspection.
This had led to a highly restricted regime which fed, rather than addressed, the cycle of violence and retribution in which so many prisoners were trapped.
HM Inspectorate of Prisons report
How inspectors graded Isis
The inspectorate judges prisons against four healthy prison tests: safety, respect, purposeful activity and preparation for release. Purposeful activity covers education, work and time out of cell. Preparation for release looks at how well a prison readies people for life after custody.
Inspectors rated Isis good for respect, the highest of the four possible grades. They judged safety, purposeful activity and preparation for release not sufficiently good.
That marks progress. At the full inspection published in December 2022, inspectors rated purposeful activity and rehabilitation and release planning poor, the lowest grade. Safety stayed at not sufficiently good, and respect stayed at good. The inspectorate also carried out an independent review of progress at Isis in June 2023, a follow-up visit that checks how far a prison has acted on earlier concerns.
Of the 15 concerns raised in 2022, inspectors found eight addressed and three partly addressed. Three remained unaddressed, and one no longer applied.
Violence, drugs and time locked up
The report identified 10 key concerns, five of them priorities. At the top of the list, inspectors said levels of violence remained very high. The new behaviour model had reduced incidents in many areas, but it was still in its infancy.
Because men no longer necessarily lived alongside friends or fellow gang members, a higher than usual proportion said they felt afraid. Illicit drugs were widely available. Positive drug test rates were high, and the number of drug finds had increased.
Use of PAVA, an incapacitant spray, was high. Inspectors found its use proportionate in most cases. In some footage they reviewed, however, staff had clearly used it too readily.
The work and training offer had improved, but the prison took too long to allocate men to activities. Too many places were part time, and a minority of men had no activity at all. As a result, many spent up to 22 hours a day locked in their cells. Attendance at education was disappointingly low, in a jail where many of the young men had underachieved at school.
Other concerns covered early days in custody, dirty residential areas, limited chances to build computer skills, and too little contact with prison offender managers. Inspectors also found weak oversight of public protection risks.
Strong relationships and healthcare
Inspectors described relationships between staff and prisoners as a strength. With support from the prison group director, the governor had raised staffing levels and improved officers’ skills. Retention had improved and sickness levels had fallen. Reverse mentoring had broken down barriers and improved understanding between prisoners and officers.
Healthcare stood out. The report said: “Healthcare at Isis was particularly impressive.” An integrated team worked with prison staff to meet primary and mental health needs across the prison.
Inspectors recorded nine examples of notable positive practice. These included individual behaviour plans on the Growth spur and regular weapons amnesties promoted by peer mentors. A group therapy programme called Changing the Game had improved access to therapy for black and minority ethnic men involved with gangs and serious violence. Men nearing release could also have an extended visit with their family to plan their return home.
The prison was cleaner than at the last inspection but still not clean enough. Inspectors said leaders needed to hold staff and wing cleaners to account.
Charlie Taylor, HM Chief Inspector of Prisons, acknowledged that Isis is a difficult prison to run. Its population includes young men serving anything from a few weeks to life. Some 47% of prisoners were aged 18 to 21, and 70% came from minority ethnic backgrounds. The prison held 140 care leavers and had released 783 men in the previous year. He credited the long-serving governor with determined, imaginative leadership that continued to drive improvement.
About this story
This story is based on HM Inspectorate of Prisons’ report on HMP & YOI Isis, published on 9 March 2026, following an inspection that ended in December 2025. All figures and judgements are the inspectorate’s. Read the full inspection report · See the prison’s profile in our directory.
