Authorities on England's south coast have said they cannot take in any more unaccompanied child refugees and will start turning them away from Monday.
Kent County Council said it had reached the limit of safe capacity for young asylum seekers after more than 100 arrived in the first half of 2021.
It comes days after the council threatened legal action against UK government ministers over what it sees as their failure to reallocate migrants to other parts of the country.
Only 34 kilometres from France at its closest point, Kent is on the front line of cross-Channel migration to Britain and wants a voluntary transfer scheme made compulsory.
Friday’s announcement is the second stoppage on new arrivals in less than a year.
“I am profoundly saddened to be in this unthinkable position once again in such a short period of time,” the council’s Conservative leader Roger Gough said.
“As we have experienced over the past few years, there is absolutely no evidence that a voluntary national transfer scheme has kept pace with the ever-escalating new arrivals on our shores.
“Kent residents have been waiting a number of years for a long-term national solution to the ongoing disproportionate strain on local services.”
The council said more than 400 child refugees were in its care, well above a government maximum of 231.
It said the number rose from 274 since the start of the year and was “continuing to rapidly increase on a daily basis”.
The stoppage will last until enough children are transferred to other parts of Britain so that Kent can safely look after others.
The UK’s Home Office said it was revamping the transfer scheme to ease the pressure on hard-hit areas.
While the scheme will remain voluntary, it will be backed by £20 million ($28m) of extra funding.
Ministers plan to create a rota of migrant transfers so that towns and cities can plan ahead for when they can expect new arrivals.
“The Home Office is grateful for the role Kent County Council has played in supporting unaccompanied asylum-seeking children,” a representative for the department said.
“We have provided them with substantial operational support, including transferring those in need of support to other local authorities in the UK.”
A member of a refugee charity told The National this week that proper funding from the UK government could "fix this issue overnight".
“It’s an investment in young people that’s going to pay off,” Bridget Chapman of Kent Refugee Action Network said.
“It’s framed as a problem that’s got to be solved when actually these young people are an amazing asset to our community.”