The UK’s one in, one out treaty with France is under scrutiny after human rights organisations said hundreds of people returned to France since September 2025 can no longer be located. That loss of contact includes a claimed minimum of 41 age-disputed children, the NGOs told parliamentarians this week.
About 1,400 people who arrived in the UK on small boats have been returned to France since September 2025, roughly 4% of the 32,000 who crossed the Channel since the deal was signed. The treaty, agreed last year, allows the UK to return small-boat arrivals to France in exchange for legal transfers to the UK. It was amended to permit people who return to the UK in lorries to be sent back to France a second time.
NGO representatives told a parliamentary meeting that many of those forcibly returned are now living underground across Europe, and that French politicians say only about 200 of the people returned remain in contact with French authorities. Campaigners said disappearances followed hostility from French officials, pressure to go back to home countries, or the risk of transfer on to other European states they had passed through.
Maddie Harris, director of the Humans For Rights Network, told MPs her organisation and others had compiled a list of at least 41 age-disputed children who had been removed. She said, "We support many children detained under this scheme and attempt to secure their release. However, at least 41 children have been removed from the UK to France and their whereabouts is currently unknown. The vast majority of these children have experienced acute violence and exploitation and are now without protection somewhere in Europe."
The Home Office rejected the claim about age disputes in a statement to MPs, saying, "This is categorically untrue. Nobody has been returned to France where their age is in dispute. Every detained person is advised of their right to legal representation and how they can obtain such representation within 24 hours of arrival at an immigration removal centre. Age assessments are carried out to maintain the integrity of our border, while ensuring those genuinely under 18 receive the appropriate support." Independent monitoring boards have reported that almost a hundred children were identified as unlawfully detained as adults in relation to the scheme.
Health and humanitarian agencies also raised concerns about the condition of people being returned. Nihal Osman, a programme coordinator for Médecins Sans Frontières, said returns were "deeply concerning," and described many returnees as showing severe psychological symptoms including flashbacks, acute anxiety, self-harm and suicidal thoughts.
The treaty is due to expire on 1 October. The home secretary, Shabana Mahmood, is reportedly pushing to extend and scale up the scheme while the French government has signalled it wants expansion of the approach Europe-wide. Parliamentary chairs and rights groups said the reported disappearances, detention concerns and limited post-return oversight will be central to any decision on whether to renew or broaden the arrangement.
