The prison was given a full inspection in November/December 2025, the full report can be read on the HM Inspectorate of Prisons website, just follow the links below. In their latest report the inspectors said:
HMP & YOI Isis is a category C training and resettlement prison and young offender institution for young men aged 18 to 27, in Thamesmead, south-east London, run by HM Prison and Probation Service on a site it shares with HMP Belmarsh, holding 577 prisoners against an operational capacity of 628, with 47% aged 18 to 21, 70% from Black and minority ethnic backgrounds, and 140 care leavers among the population. Inspectors rated safety Not Sufficiently Good, unchanged, respect Good, unchanged, purposeful activity Not Sufficiently Good, an improvement from Poor, and preparation for release Not Sufficiently Good, also improved from Poor.
Seventy-eight per cent of prisoners said they had a named officer, and inspectors praised determined, imaginative leadership from the governor, including a new violence-reduction “Peace Strategy” behaviour-management model that had already significantly reduced assaults on staff. Healthcare was described as particularly impressive, with well-integrated primary and mental health care, no deaths in custody since 2020, and self-harm incidents down around 22% since the last inspection. Education completion rates were strong, with nearly all prisoners who started a qualification completing it, and good employer links into construction and logistics.
Inspectors raised five priority concerns: violence remained too high, with 31% of prisoners saying they felt unsafe; drug use was a problem, with a 25% positive mandatory drug test rate, mainly synthetic cannabinoids; 36% of prisoners were locked up during the core working day and only 25% were engaged in purposeful activity; too many activity places were part-time only with a slow allocation process leaving some unemployed; and education attendance was disappointingly low given the population’s history of educational underachievement. Inspectors also found weak early-days and induction processes, insufficiently clean residential units, and ineffective oversight of licence and restriction breaches.
Charlie Taylor
HM Chief Inspector of Prisons
March 2026
To read the full reports, go to the HM Inspectorate of Prisons website or follow the links below:
| Inspection report (PDF), Report on an unannounced inspection of HMP & YOI Isis by HM Chief Inspector of Prisons (18 November–4 December 2025, published 9 March 2026) | Easy read summary of the 2025 inspection report |
| Action plan, HM Prison and Probation Service action plan in response to the 2025 inspection of HMP & YOI Isis | |