THE teenage daughter of double child killer Mary Bell only learned the dreadful truth about her mother in the early hours of yesterday morning, a court has been told.

The full background was revealed when police took a decision to remove mother and child from their home to guarantee their safety because the house was being besieged by the media.

The deputy chief constable of the area has expressed concern about possible vigilante activity if the identity of the family is published and has said there would be a real risk of physical injury to the child if that happened.

At the Court of Session last night Lady Cosgrove granted an order banning the press in Scotland from publishing any information that would lead to the identity of the teenager, who is a ward of court in England. The order was sought by Northumberland County Council, against a number of Scottish newspapers including The Herald but opposed only by The Scotsman Publications and the Scottish Daily Record and Sunday Mail Ltd.

The Herald did not oppose the granting of the order because we had no intention of publishing any information which would have led to the child or her mother being publicly identified.

Lady Cosgrove was told that identification of the child in the media would add to the emotional and psychological trauma she had already suffered by learning about her mother's past. The judge said: ''We don't want to visit the sins of the mother on the child.''

Mr Michael Bell, counsel for the county council, explained that the mother, formerly known as Mary Bell, was convicted of manslaughter in Newcastle in 1968 when she was 11 and released on licence in 1980. Her daughter was born in 1984 and made a ward of court in the Family Division of the High Court shortly afterwards.

There was also an order banning the media from disclosing information that could identify her.

Now, the mother had contributed by way of interviews to a book on her life by the author Gitta Sereny. The book Cries Unheard was due to be published in The Times and this had caused great media excitement over the life and circumstances of Mary Bell.

The house in which the mother and daughter were now living had become besieged by journalists.

''At 4am this morning the situation became so difficult that the deputy chief constable took the view that the only way of guaranteeing the safety of both mother and child was to remove them from the home. They are now residing at an address not to be disclosed.

''The result of this is that for the first time in 14 years the child became aware early this morning of the mother's background.''

The county council, which was curator of the child, had now become aware that a number of newspapers were planning to publish details about the mother and full details about the child.

''Obviously there is the greatest apprehension that publication will cause further emotional distress and long-term psychological damage and that in itself justifies the granting of the petition (for interim interdict).

Mr Bell informed the court that earlier in the day contact had been made with the deputy chief constable for the area where mother and daughter were living. ''He has stated directly that if publication takes place he considers that there is a real risk of physical injury to the child if some sort of demonstration or quasi-vigilante action were to take place.''

He was not sure that the police could control such a situation.

Mr Bell stressed he was seeking only to restrict publication of details relating to the identity of the child. He was in no way attempting to restrict the right to comment on the mother.

The real concern was that the press in England was already restricted from identifying the child but without a court order the media in Scotland would have free rein, possibly even to publish photographs of her.

He argued that this could lead to potentially massive emotional, psychological, and possibly even physical damage to the child.

Mrs Anne Smith QC, for The Scotsman and Daily Record, argued that a banning order should not be granted.

She explained that the media

interest had been caused by the fact that the mother had chosen to become involved in a book and contended that a great deal of information had already been published from which the child could be identified.

Lady Cosgrove said she saw nothing in the press cuttings she had been given which would, for example, enable her to be identified by a child at the same school. The stage had been reached where people in the same street could add two and two and make four.

Mrs Smith said that ''horrendous, disturbing and distressing damage'' had been done to the child by the knowledge of who her mother was and it was a matter of great regret to everybody that she had to learn the story about her mother at this stage in her life.

Tragically, however, the damage had been done.

Lady Cosgrove said: ''Why should we compound that damage?'' The judge also expressed concern about the reaction to publication. ''It's a matter of concern to the courts that vigilante groups may take action in these situations.''

The judge said she had not been persuaded that the stage had been reached where the damage had passed and nothing could be done and made an order banning the publication of details which would lead to the child being identified.

q The Prime Minister yesterday said that it was ''inherently repugnant'' that people should make money out of terrible crimes and hinted he might consider banning certain criminals for life from profiting from books about their offences.

Bell's lover described her last night as a ''warm, wonderful woman'' who deserved more money than she has been paid for telling her life story.