94 children wrongly detained as adults
Home Office figures show 94 of 304 age-disputed arrivals under the France returns deal were children held in adult detention.
Nearly 100 children were detained as adults in UK removal centres under the government’s returns deal with France, according to Home Office figures disclosed to a minister this month.
The figures sit in a letter from Jane Leech, interim chair of the Independent Monitoring Boards, to Home Office minister Anna Turley. They show that of 304 age-disputed cases arising from the scheme between 15 August 2025 and 1 May 2026, 94, almost a third, were later confirmed to be children who had been held as adults, in breach of the department’s own rule limiting the detention of unaccompanied children to 24 hours. One man was held for 27 weeks.
Children detained as adults under a deal that bars them
The scheme, known inside the Home Office as Operation Hillmore, was launched a year ago by then-home secretary Yvette Cooper as “one in, one out”: for every migrant returned to France, the UK admits one person judged to have a legitimate claim. The treaty that governs it explicitly excludes unaccompanied minors from transfer. Shabana Mahmood inherited the scheme when she became home secretary in September’s reshuffle, and it is now her department’s figures showing children being funnelled into it anyway.
Some of what happened to them next is set out in Leech’s letter. In two cases seen by the Heathrow monitoring board, it took more than 40 days from arrival at a removal centre to an age assessment. One detainee transferred from Manston to Gatwick had tuberculosis. Detainees have been separated from family members they travelled with, which Leech called “a particularly damaging impact”. A Sudanese torture survivor with reasonable grounds to be treated as a trafficking victim was forcibly removed to France under the scheme in November; the High Court ruled the removal unlawful in July and ordered his return.
This is not confined to one scheme. Refugee Council research has found more than 1,300 asylum-seeking children wrongly assessed and treated as adults by the Home Office system-wide over 18 months. Imran Hussain, the charity’s executive director of external affairs, said children are “too often” treated as adults and “put into unsafe situations, at risk of abuse and neglect”.
The Home Office says age assessments are “essential to maintaining the integrity of our border” and points to an AI tool due next year. Leech’s letter asks for something narrower and harder to dodge: that people whose age is disputed should not be locked up while officials work it out. Until that changes, the department doing the assessing is also the department doing the detaining.
