Gambrah v Director of HMP Thameside: six-day unlawful detention highlights systemic failures at private prison

A privately managed prison unlawfully detained a young man for almost six days after a Crown Court judge ordered his immediate release, the High Court has found, in a case that exposes persistent institutional failures at HMP Thameside — operated by Serco under contract with His Majesty's Prison and Probation Service.

Jayden Gambrah was sentenced on 20 February 2026 at Inner London Crown Court to a 24-month Detention and Training Order (DTO), with credit for time served. He was entitled to immediate release. Despite the court transmitting sentencing documentation to the prison the same evening, no custody staff were on duty to receive it. None were rostered over the weekend. The Offender Management Unit (OMU) inbox went unmonitored for two days.

When staff returned on 23 February, rather than effecting release, the prison became mired in an internal query about whether a DTO could lawfully be imposed on an individual aged 18. The answer — that section 29 of the Children and Young Persons Act 1963 permits a DTO where the defendant turned 18 during proceedings — was neither complex nor obscure. The sentencing judge's own email, sent on 24 February, confirmed the matter had been addressed at length during the hearing. Still, Mr Gambrah remained in custody.

Over the following days, his solicitor, Alex Pierides of Faradays Solicitors, sent repeated emails to both the OMU and Custody Team, expressly cited the principle from Niagui v The Governor of HMP Wandsworth [2022] that a solicitor's complaint of unlawful detention "demands a substantive response as a matter of urgency", and warned that an application for a writ of habeas corpus would follow. Not one communication received a substantive reply. When Mr Pierides telephoned on 25 February and asked to speak to the Duty Governor, he was told the Governor was at lunch; the Custody Team, he was informed, was available only for "emergencies and prisoner welfare issues" — a categorisation the prison appeared incapable of applying to its own client's unlawful detention.

A Part 8 claim was filed out of hours on the evening of 25 February. Mrs Justice Hill, sitting as duty judge, listed a hearing for the following afternoon and ordered the Defendant to file a witness statement by noon. That order was not complied with. When the hearing began at 2.00 pm on 26 February, the Defendant was neither present nor represented. Counsel attended part-way through and confirmed release was anticipated. Mr Gambrah was finally discharged at 3.47 pm — nearly six days after he became entitled to liberty.

By consent order dated 6 March 2026, Serco agreed to pay £5,000 in damages for unlawful detention and £5,500 in costs. Mrs Justice Hill nonetheless issued a public judgement, observing that the period of unlawful detention in this case — considerably longer than the one to three days condemned in Niagui, Kim v The Governor of HMP Wandsworth [2024], and Bashir v The Governor of HMP Pentonville [2025] — was "particularly troubling" given Mr Gambrah's age and status as a former looked-after child.

The judgement identifies eight distinct failings, including the absence of any weekend custody cover, a lack of staff training on the fundamental presumption against detention without lawful authority, failure to escalate correspondence, non-compliance with a court order, and the absence of any policy implementing the principles Chamberlain J set out in Niagui as long ago as November 2022.

Serco's Director of the prison, Jonathan Bratt, issued a Director's Notice to staff on 2 March 2026 and committed to increased weekend staffing. Mrs Justice Hill welcomed these steps whilst noting the Notice was "very brief" and risked being read as applying only when the words "habeas corpus" were explicitly used, rather than wherever unlawful detention was genuinely in issue.

The case underlines that private contractors operating prisons carry identical legal obligations to HMPPS with respect to false imprisonment. A contractual staffing model that leaves no custody staff available at weekends does not displace those obligations — it simply makes compliance harder, and makes unlawful detention more likely.

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