Image copyright Science Photo Library Image caption The tags will allow the children to be reunited with their parents

The adult members of two families will have electronic tags fitted because of fears they could take children to areas controlled by Islamic State militants.

Senior family judge Sir James Munby ruled the measure was necessary to end the parents' separation from the children who were in foster care.

The decision would at the same time ensure the children's safety, he said.

The Ministry of Justice (MoJ) had raised concerns about the move, which it called "unprecedented".

Local authorities who placed the children in foster care opposed them being returned to their families before full fact-finding hearings in the family courts later this year.

'Realistic view'

But Sir James, president of the Family Division of the High Court, said the risk of the children being taken from the UK was "very small indeed" and counter-balanced by their need to be returned to the care of their parents.

The judge announced he was intending to make the tagging orders in a judgement he gave last week but delayed making the decision in order to consider the MoJ's concerns.

Sir James said: "I accept that there is some degree of risk of successful flight.

"But, taking a realistic view, though not forgetting that we are here in the realm of unknown unknowns, my considered assessment is that the degree of that risk is very small indeed, so small that it is counter-balanced by the children's welfare needs to be returned to parental care.

"I should add, to make plain, that in relation to their welfare, the benefits all of these children will derive from being returned to their parents clearly, in my judgement, outweigh any and all of such contrary welfare arguments."