A woman who coached her three children to say "negative things" about their father without justification must have the youngsters taken from her care, a family court judge has ruled.

Judge Charles Atkins decided that the children must move to live with their father.

He said the mother was "very hostile and bitter" towards he ex-husband and was trying to undermine their relationship with him.

Her behaviour was causing the youngsters psychological damage, he said.

The judge outlined his decision in a written ruling after analysing evidence at a private hearing at a family court in Croydon last year.

He indicated that the children had stayed with the woman following a divorce but had regularly seen their father.

Social services bosses at Sutton Council have welfare responsibility for the children and had raised concern about the effect the woman's behaviour was having.

The judge said the children, none of whom have yet reached their teens, could not be identified.

"I am afraid I am satisfied, and for whatever reason, [the woman] is very hostile and bitter towards the father of the children, and she makes this plain, even in front of the children," said Judge Atkins.

"She has nothing positive to say about him and many negative things."

He added: "I am satisfied that she does try to undermine his relationship with the children.

"She repeats false allegations to the children and those allegations are of a serious nature, such as wishing to poison them.

"She regularly coaches the children to say negative things about the father without any justification."

The judge said he had to decide what was best for the children.

"I have come to the conclusion that it is in the best interests of the children for them to be transferred to the care of their father," he said.

"I am satisfied that this is a mother that has caused, and is like to continue to cause, significant harm to the children, including by actually trying to undermine their relationship with the father."

He added: "I think her behaviour is emotionally abusive of them and psychologically damaging to them."