Campaign groups have demanded the UK authorities rethink procedures for handling teenage refugees from Hong Kong, after claiming that several had been misidentified as trafficking victims and endured traumatic treatment.

A 16-year-old boy who arrived in April said his parents had been left without news of his whereabouts for a month after his phone was confiscated by Border Force officers on arrival in the UK — a safeguard intended to block contact from traffickers. No one acted on the request of Adam, not his real name, to let his family know he was safe.

Johnny Patterson, policy director at Hong Kong Watch, a campaign group, said Adam’s story invited “important questions” about the Home Office’s treatment of young asylum seekers and it was “unacceptable” he had been unable to contact his parents.

The child migrant issue is the latest question over the UK’s readiness to handle up to 300,000 Hong Kongers expected over the next five years to flee to Britain from increasingly authoritarian Chinese rule.

Jabez Lam, centre manager for Hackney Chinese Community Services, a charity in London that helps new arrivals, said local support groups thought that hundreds of schoolchildren might travel alone to the UK to avoid arrest over their participation in pro-democracy protests in the territory in 2019 and 2020.

“Although the intention [of the safeguards] is good, a lot more needs to be done to make the under-age minors feel safe,” Lam said.

Hillingdon Council, which covers Heathrow airport, the main port of arrival for those fleeing Hong Kong, said it had received 14 unaccompanied child migrants from the territory since November last year. Adam, the 16-year-old boy, had arrived at another airport.

It was “established protocol” by UK authorities under some circumstances to treat unaccompanied minors as potential victims of sex trafficking, Lam said. Several of the migrants had their mobile devices removed upon arrival and were barred from leaving the homes where they were placed, he added.

It can be an indicator that a person is being trafficked if their ticket has been paid for by a non-family member. However, Adam said he had paid for his own flight by taking a part-time job in Hong Kong and selling his bicycle.

Lam said none of four migrants who contacted him had been placed with a Cantonese-speaking family and two had not yet received requested mental health support.

Fred Wong, a representative of the charity Hong Kong Assistance and Resettlement Community, agreed that the procedures needed to be revised.

The UK announced in January a route to settlement and citizenship for holders of the British National (Overseas) passport, issued to many residents of the territory while it was under British rule. The route is largely barred to those born after 1997, when Britain handed back sovereignty to China.

There were 95 asylum claims in the UK from Hong Kong citizens in the year to March 31, against just 14 the previous year. There had been no unaccompanied child migrants from the territory recorded in official asylum statistics between 2017, when unaccompanied children were first recorded as a separate group, and the fourth quarter of 2020.

Adam said Border Force officers took away all his belongings, including his phone, when he announced that he was seeking asylum because of his role in the Hong Kong protests. They questioned him for eight hours before handing him to social workers who took him to a foster home, he said.

When his phone was returned, he found no one had contacted his family. “My parents thought I’d gone missing for a month,” Adam said through an interpreter.

The foster family appeared to know little about events in Hong Kong, Adam added. He had told them of his history of anxiety and depression and requested help with seeking treatment but they had not so far raised the issue with his social worker, he said.

“This is one area in particular that definitely needs to improve,” he added.

The UK government said it recognised unaccompanied asylum-seeking children were often some of the most vulnerable in society and that local authorities faced “rising pressure on their services”.

However, it said local authorities were responsible for all “looked-after” minors in their area, a term that includes those in foster care and homes and those arriving unaccompanied from overseas.

“They must consider the linguistic and cultural needs of each child when making decisions about placements, as well as what support from local mental health services is required,” it said.

The local authority responsible for Adam’s care, which is not being named to protect his identity, said it “diligently” followed legislation and statutory guidance.

Hillingdon Council said it was satisfied appropriate procedures were in place to respond with “respect and compassion” to unaccompanied young people fleeing persecution.

“All have received the best available support, including interpreters fluent in Cantonese, access to an immigration solicitor and legal advice,” it said.

The children had also been allocated a social worker and contact with Coram Voice, a charity, and given access to the council’s psychology services, it added.