Sue Dickinson, 41, brought the High Court action for negligence and breach of duty against Cornwall County Council after the death of Caroline, on 18 July 1996. She wept at the news that her case had failed.
It was claimed that Cornwall County Council was in breach of duty because it failed to take reasonable care during the trip to a youth hostel in Brittany. Teachers from Launceston Community College should have ensured that hostel staff locked the outside doors at night, it was said.
Caroline was raped and asphyxiated while on an activities week trip with 40 pupils in the village of Pleine Fougeres, supervised by four teachers.
She was found dead on the mattress on which she slept in a first-floor youth hostel bedroom that she was sharing with four other girls. None of the doors were locked.
The intruder who broke into the hostel is being hunted by French police. They revealed this week that a man, who may have been working at a building site nearby at the time of the murder, was a new suspect. The man was described as a "caveman" character with long straggly hair, dark eyebrows and a broad nose.
Mr Justice Steel at the High Court, sitting in Exeter, yesterday dismissed Mrs Dickinson's claim saying that she had not proved a case that staff supervising the trip were at fault.
The judge added that, even if the staff were at fault, the risk of someone coming through the unlocked outside doors and attacking Caroline was so low that it was extremely difficult for anyone to have predicted it and have taken precautionary measures.
The judge said: "I recognise the dreadful anguish to which the claimant has been exposed, exacerbated by the, as yet, fruitless outcome of the police investigation. But that does not allow me to find the defendants are liable."
Mrs Dickinson, from Launceston, was in court with her former husband John, 43, from Bodmin, Caroline's father.
During the earlier hearing, which was held in Plymouth, Mrs Dickinson said: "I entrusted the care of my daughter to the school and I feel they owed Caroline a duty of care."
Outside court yesterday, Mrs Dickinson's solicitor, Ian Langsford, said: "Sue Dickinson is naturally disappointed that the claim has failed today."
He added: "In bringing this action Sue rightly wanted to know more about the circumstances in which her daughter died ... finally it is Sue's hope that this case will help to prevent such a tragedy ever happening again."
Cornwall County Council's director of education Jonathan Harris said: "We believe that in this case all our staff acted sensibly and responsibly and could not be held responsible for the tragic events which occurred. We are pleased that the judge reached a similar conclusion."Reuse content