Wardship proceedings in the case of the row over the adoption of twins over the Internet were issued today by Flintshire Education and Children's Services.
The twins, Belinda and Kimberley will stay "safe and well" in the care of social workers before the battle for their custody starts in Birmingham on Tuesday, Flintshire County Council said.
Alan and Judith Kilshaw, of Buckley, north Wales, the couple who 'adopted' the six-month-old babies in America, today kept a low profile at a hotel in Lytham St Anne's, close to Blackpool, after days of media interviews.
Mr Keith McDonogh, Flintshire County Council's director of Education and Children's Services, said the wardship proceedings were issued this morning in the family division of the Birmingham District Registry of the High Court.
"We have always believed that the future of these children should be determined by a considered legal process in view of all the issues involved, including complex legal, practical and international dimensions," he said.
Mrs Kilshaw, 47, and her husband, a 45-year-old solicitor, say they will do whatever is necessary to get the twins back.
"We are fighting a very powerful strong body. It's like David and Goliath," said Mrs Kilshaw, who has an 18-year-old daughter Cayley from a previous relationship.
The couple's solicitor, Ms Dianne Miller, had been expecting Flintshire County Council to try to make the twins wards of court.
"After the close of business yesterday, a colleague rang me from the office to say that an unsealed fax had been received from Flintshire County Council making an application this morning in the High Court at Birmingham," she said.
"I have heard nothing, but as far as my client is concerned the adoption is perfectly legal," she added.
The couple, whose actions have sparked international outrage, fear social services will also take away their natural children, Ms Miller said.
She said the couple believed social workers could seize their two young sons unless they were allowed to question the boys.
"My clients have no objection to social services speaking to their two sons," family law specialist Ms Miller told BBC News 24.
"But there appears to be an implied threat behind that, that if they are not spoken to immediately some proceedings will be taken in relation to the children." The boys, James, seven, and Rupert, four, had lived with their parents "all their lives" and there was no proof Mr and Mrs Kilshaw had raised them badly.
"If any application is made in relation to those children my clients will be absolutely opposed to it."
Asked if she thought it was likely the couple's sons could be taken, Ms Miller replied: "Yes, that is my fear."
Reuters