Young asylum seekers in the UK are more than twice as likely to be assessed as adults by immigration officers as by social workers, according to Home Office data.

Between July 2025 and March 2026, 4,320 initial age decisions made by immigration officials found 1,363 new arrivals (32%) to be children.

During the same period, out of 1,756 completed age assessments carried out by local authority social workers, 1,198 individuals (68%) were recorded as children.

The information, which the Home Office is publishing for the first time, is being released at a time when some politicians have accused adult asylum seekers of pretending to be children.

The Home Office says initial assessments by immigration officers are typically made “at pace”, often with limited or incomplete information. Local authority age assessments are often conducted over a period of six to eight weeks.

The Home Office has established a national age assessment board (NAAB) with its own in-house social workers to conduct age assessments of age-disputed young asylum seekers. It is proposing strengthening the weight given to its own in-house assessments.

Many children from countries such as Afghanistan, Sudan and Eritrea do not have passports or birth certificates, either because they have never had them or because they have been destroyed, lost or taken.

In thousands of cases, UK border officials decide a person’s age based on a visual assessment of their “appearance and demeanour”. If they think an individual looks significantly over 18, they will move them straight to adult accommodation or immigration detention.

A report from the independent chief inspector of borders and immigration last year highlighted a decade of concerns around the Home Office’s “‘perfunctory’ visual assessments”. It found that the Home Office still relied on generic physical characteristics and that young people felt put under pressure into signing documents stating they were adults.

Some children wrongly treated as adults have been charged with immigration offences, spending periods of time in custody with adults in adult prisons or held in immigration removal centres before being removed to France under the “one in, one out” returns agreement.

Kamena Dorling, the director of policy at human rights charity the Helen Bamber Foundation, said: “It is a huge step forward that the Home Office has finally published its own full statistics on age disputes, showing for the first time how many children are taken into care from the adult asylum system. Finally we have the data to allow us to understand the full scale of this crisis.

“Despite the mounting evidence of the profound harm being caused, the Home Office continues its practice of wrongly assessing children, who come to the UK alone to seek protection, as adults.

“The Home Office must acknowledge this is as a serious safeguarding failure and take immediate steps to ensure that border officials only dispute a child’s claimed age in exceptional circumstances.”

New research from the Jesuit Refugee Service (JRS) and the Humans For Rights Network has found that since the one in, one out scheme started last August, at least 141 age-disputed young people have been detained under the scheme.

At least 64 of these either have subsequently been found to be children by local authorities or are in their care pending further inquiries. A further 18 have been removed to France.

Sophie Cartwright, a senior policy officer at JRS UK, said: “It is horrifying that children are being detained – frequently – under the one in, one out scheme. Often they have already experienced torture, trafficking or other serious trauma. The whole experience is hugely harmful for them and puts them in danger. Some have been removed to France, where they are at risk of destitution.”

The Home Office has proposed an end to local authority autonomy over asylum seeker age assessments and making assessments from the NAAB binding.

Prof Sam Baron, the interim chief executive of the British Association of Social Workers, condemned these proposals. She said: “With every further move that the Home Office makes on age assessments, it becomes clearer that for them, age assessments are for the purposes of immigration enforcement.

“There is no reason that the NAAB should ever have been created when local authorities are more than capable of carrying out age assessments with support and training. Local authorities should think twice before entrusting the Home Office with these assessments and should fight back against this move to further minimise the role of local authorities.”

A Home Office spokesperson said in response to the report about age-disputed child asylum seekers being sent to France as part of the one in, one out deal: “We completely reject these claims. The safety and wellbeing of children in care is paramount, and individuals are not removed to France where their age is in dispute.”

The spokesperson added: “We have robust processes in place to verify and assess an individual’s age and where uncertainty on age remains, an individual will be treated as a child. The local authority will then make a thorough assessment using well established age-assessment techniques.

“We will continue work to modernise and strengthen that process in the coming months through the testing of fast and effective facial age estimation technology.”