Home Office officials have been ordered to pass on "highly sensitive" police information about an "Islamic extremist" whose child is at the centre of family court litigation.
Social services bosses in the London Borough of Tower Hamlets launched care proceedings in the Family Division of the High Court in London after discovering that the child's father was thought to have fought with an extremist group in Syria.
A High Court judge overseeing private family court hearings has told Home Secretary Amber Rudd to disclose police information so that it can be analysed by lawyers involved in the care proceedings.
Mrs Justice Pauffley said any family court judge asked to make decisions about the child's future would need "any information" about extremist or radicalised conduct by adults in the child's family.
Detail of the disclosure order has emerged in a written ruling published by Mrs Justice Pauffley following the latest round of litigation.
The judge did not identify the family involved.
She said Tower Hamlets Council social workers were currently supervising the child's care.
Mrs Justice Pauffley said she had heard argument about the need for information disclosure from lawyers representing Tower Hamlets Council, the child's parents and the Home Office.
She said social services bosses and judges involved in the litigation had a "legitimate interest" in sensitive police material in Home Office hands.
A barrister representing Tower Hamlets Council told Mrs Justice Pauffley how social services bosses had decided that family court judges needed to make decisions about the child's future after being given some information about the father by Metropolitan Police counter-terrorism specialists.
Sarah Morgan QC told how information received suggested that the man was an "Islamic extremist" who had travelled to Syria in 2013 and 2015 and fought with an "Islamic extremist group".
Mrs Justice Pauffley said the child and the parents had a right to a fair family court trial.
The judge suggested that it would be difficult to ensure fairness if "highly sensitive" but relevant Home Office information about the family was not considered during the care proceedings.