Caroline's mother, Sue Dickinson, is claiming damages for negligence from the education authority responsible for Launceston Community College, which organised the trip.

Caroline, 13, was raped and asphyxiated in a dormatory at the hostel in Pleine Fougeres, Brittany, three years ago.

At the high court in Plymouth, Tim Kerr, acting for the education authority, said it was not responsible for the two external doors to the hostel being unlocked on the night of the murder.

Dangerous precedent

Mr Kerr, in his closing speech, said the investigation, planning, execution and arrangements for the trip, and the trip itself, were "competent, diligent and meticulous".

He said it was not the responsibilty of education authority employees to ensure the doors to the hostel were locked.

The attack was not a reasonably foreseeable consequence of the doors being unlocked, Mr Kerr said.

He argued that if it was decided the education authority was liable in this case, it would set a precedent that may discourage schools and colleges from organising future trips.

Mrs Dickinson told the court on Wednesday that she could not understand why children had been allowed to sleep in unlocked rooms in an insecure building.

She said the children would "be obviously vulnerable to prowlers and others".

The teacher who organised the trip, Elizabeth Barker told the court on Wednesday that the thought of intruders did not enter her mind.