A local authority was today found not guilty of breaching health and safety laws after a 14-year-old schoolboy died on a caving trip.
Joe Lister drowned when water swept through Manchester Hole Cave in the Yorkshire Dales during a school trip in November 2005.
North Yorkshire County Council, which owns and operates the outdoor education centre involved in the trip, was today cleared of two charges of failing to ensure the health and safety of its staff and others.
A jury at Leeds Crown Court took around nine hours to reach the not guilty verdicts.
Joe, from Tadcaster, North Yorkshire, was one of 10 pupils and three adults taking part in the caving trip organised by the council-run Bewerley Park Centre.
The group got into difficulties when water in the cave began rising rapidly, forcing them to have to swim to safety through a tunnel known as The Crawl - which is 12 metres (just under 40ft) long and less than one metre (3.28ft) high at its lowest point.
Joe drowned in the cave and was later found by a rescuer with his head torch still on but without his Wellington boots.
North Yorkshire County Council was charged with two counts under the Health and Safety at Work Act (1974).
Mr Justice Wilkie said: "In the end, the jury has concluded that there was nothing which the North Yorkshire County Council could reasonably have done to have avoided what happened.
"It is right and proper that they should have reached such a conclusion.
"I trust, however, that this will not be regarded as a reason for any complacency or self-congratulation by those involved in organising and delivering these activities.
"For the one thing this case has taught is that, however great the expertise, and however easy the cave, they can be unpredictable and dangerous.
"I trust that this trial will have provided a spur for them to maximise their understanding of the systems within which they work and to seek to ensure that the activities are delivered in as safe a way as possible."
Outside court, Joe's father Martin Lister read a statement, flanked by his wife, Paula, and other members of his family.
Mr Lister said: "We are very disappointed with the verdict reached by the jury in this case. We feel the HSE presented a compelling case."
He added: "It may be that the detailed examination in this court of the actions of North Yorkshire County Council will result in measures being taken to ensure that other young people are not exposed to the terrible and traumatic experiences described to the jury by those who were underground on that fateful day. We fervently hope so."
Pam Waldron, HSE head of operations, said: "One issue on which both parties are agreed are the benefits that outdoor activities bring to young people.
"We have never sought to prevent those benefits being realised.
"The Health and Safety Executive is not about avoiding risk, it's not about absolute safety. What we do expect is that significant risks are identified and properly managed.
"Our thoughts at this time are with Joe's family who have been immensely dignified throughout what must have been for them a very long and painful process."
Earlier, the judge also praised the Lister family for their "courage" as they followed the evidence, "much of which will have been awful to hear and some of which must have seemed very far removed from the events of that day".
The judge also singled out another member of Joe's group, Carly Walton, and 17-year-old trainee instructor Jenny Wheelhouse for praise.
He said: "By their prompt and decisive actions, Carly Walton and Jenny Wheelhouse probably saved the life of another member of the party and they have my particular admiration."
The judge said outdoor activity centres "perform an invaluable educational function".
He said he was impressed by the seriousness with which the staff at Bewerley Park undertook their work.
The judge also said it was right that the prosecution was brought as it provided the opportunity for a full examination of what happened in the tragic incident.