A High Court judge is to investigate how three sisters all aged under 10 each got a sexually transmitted infection.
The children were found to have the infections in summer 2018 after concerns over their welfare in months prior.
Abuse concerns were raised after the family was twice evicted from homes and spent a month in temporary accommodation.
The children are now in foster care and social service bosses looking after them began family court litigation nearly a year ago.
A family court judge considered the case at private hearings in London, concluding the girls' father might have caused the infection.
The father appealed against that finding and now further detail of the case has emerged as a result of three Court of Appeal judges examining issues at a public Court of Appeal hearing in London in late March.
In a ruling, Lord Justice Peter Jackson, Lady Justice King and Lord Justice Lindblom have now said they are not satisfied with the family court judge's finding.
They say a judge based in the Family Division of the High Court in London must take charge and review the case.
Appeal judges said staff at Islington Council now had responsibility for the children and had begun litigation.
They also told how the sisters and their parents moved in and out of London in recent years, adding the family had been known to social workers for nearly a decade.
The family has not been identified in the ruling.
