A nine-year-old girl whose two "dangerous" older brothers pose a risk to her must leave home and live with a foster carer, a family court judge has decided.
Judge Simon Wood said both brothers are members of gangs, have violent histories and are "very dangerous young men".
The judge said the girl has two older sisters whose behaviour is also concerning.
They had been victims of child sexual exploitation, and intelligence suggested that they are now "procurers of it".
The judge said all four siblings had been implicated in a major police operation.
He said the girl had been living with her mother, who wanted her to stay at home.
But he concluded that the woman could not protect her daughter and approved a social workers' plan for long-term foster care.
Judge Wood outlined detail of the case in a written ruling after analysing evidence at a recent private family court hearing in Newcastle-upon-Tyne.
Council social services bosses with responsibility for the girl's welfare had asked him to make decisions about her future care.
The judge said the girl could not be identified in media reports of the case and has not named the council involved.
The girl was born in the UK, he said.
Her mother and father and brothers and sisters moved to Britain from Africa more than a decade ago.
Judge Wood said the family had come to the attention of social workers and police not long after arriving in the UK and the girl had been the subject of a child protection plan for several years.
"The professionals who have had full access to all the information are unanimous in their view that the risks posed to (the girl) in her mother's care cannot be managed to ensure her safety," he said.
"I very much hope that, notwithstanding the disadvantages of foster care, it will ensure her safety in the wider sense."
The judge said the case had been "difficult and distressing".
He said the girl's mother had faced a number of difficulties and her "pain" was plain to see.
"However, her two sons are very dangerous young men," he added.
"Separately, the behaviour of the (older) girls is almost as concerning.
"Probably beginning as victims of child sexual exploitation, the intelligence suggests that they are now procurers of it."
The judge said the girl would be able to stay in touch with her mother.