Prisoners have been illegally detained longer than their release date and held in “frightening” conditions at a cockroach-infested jail put into special measures by a watchdog.
Chief inspector of prisons Charlie Taylor has served an urgent notification on HMP Pentonville after an inspection discovered many inmates have been kept in prison after they should have been freed because staff “failed to calculate sentences accurately”.
The watchdog said data from the prison showed 130 inmates – 20% of those eligible for release – had been held illegally after their release date in the last six months.
The backlog in sentencing calculations also meant 10 prisoners had been released early “in error” between July 2024 and June 2025.
In a letter to the Justice Secretary, the chief inspector said arrangements for new prisoners’ first night at the north London jail and induction were “chaotic and even frightening”.
Men were held in dirty cells missing bedding, furniture, telephones and pillows, the watchdog said, while the majority of prisoners were locked in their cells for more than 22 hours a day.
The report also said 60% of prisoners were sharing cells that were designed for one person, many living areas were dirty and there was a widespread infestation of mice and cockroaches.
Inspectors took emergency action after they found care of vulnerable prisoners under constant supervision was “shockingly poor”, with one prison officer found asleep, two were reading books and another was “completely absent”.
The “unacceptable practices” in looking after these prisoners, deemed at serious risk of self-harm, were a particular concern for inspectors given three suicides at the jail in 2025.
Mr Taylor said: “Pentonville is an overcrowded, inner-city, Victorian prison with a record of poor performance over many years.
“Too many of its staff have become disillusioned about the possibility of improvement or their capacity to affect change. Yet many of its shocking failures are firmly within the control of leaders.
“The governor will need significant support and investment from HM Prison and Probation Service to strengthen his senior leadership team, re-focus on the basics, and put in place effective oversight and assurance systems to turn this failing prison around.”
A survey of prisoners also revealed 44% told inspectors they felt unsafe at the time of inspection, which the watchdog said was the highest figure recorded during his tenure as chief inspector.
Pentonville is the 10th prison to be issued with an urgent notification since November 2022, following Exeter, Cookham Wood Young Offender Institution, Woodhill, Bedford, Wandsworth, Rochester, Manchester and Winchester prisons.
The emergency measure was introduced in 2017 as a way to raise immediate concerns following an inspection, which requires a response and action plan by the Justice Secretary within 28 days.
Elsewhere, the inspector’s report also found when releases were planned, 23% of those prisoners were homeless on the day they were released, and very few had employment on release.
Reacting to the urgent notification, Prison Reform Trust chief executive Pia Sinha said: “Prisoners illegally held after they should have been released, or others released early in error, further undermine effective sentence planning and erode public confidence.
“This urgent notification must be a rallying cry for immediate action – fix the failing infrastructure, improve staff training, and treat prisoners with dignity.”
Andrew Neilson, director of campaigns at the Howard League for Penal Reform, said the findings of the inspection were “outrageous” and represent a “new low” for an overcrowded public service on the brink of collapse.
He added: “While the Government inherited a dire state of affairs in prisons, it has had more than a year to bring about change.
“As report cards go, such a dire account of dysfunction in Pentonville instils little confidence that ministers have a grip of the situation.”
Prisons minister Lord James Timpson said he visited the prison on Thursday, where the team is already working to urgently address the concerns raised by the chief inspector. An action plan will also be published in the coming weeks to support the efforts.
Lord Timpson said: “This Government will end the chaos we inherited in our jails. We are building 14,000 new prison places and reforming sentencing so our jails reduce reoffending, cut crime, and keep victims safe.”
Looking for more from MyLondon? Subscribe to our daily newsletters here for the latest and greatest updates from across London.
