A 14-year-old girl drowned as she trained for a tough moorland hiking challenge after a teacher insisted her group carry on despite terrible weather conditions, an inquest heard today.

Public schoolgirl Charlotte Shaw died after being swept away in a swollen stream on Dartmoor in Devon as she tried to cross the white water.

Her classmate Yasmin Moore, now 17, said all the teenagers in their group had asked to stop the hike but had been told to carry on by the teacher, Christopher Fuller. The group had been supervised by Fuller and other teachers on the first day of the overnight expedition in March 2007 but then set out on their own the next day to learn how to cope unsupervised.

They had been walking for around three hours when they met Fuller, by which time it was raining and hailing and they were soaked through after falling in boggy ground.

Yasmin said: "When we met Mr Fuller at Rough Tor as a group everyone decided we wanted to come off the moor. We were all wet and cold. He only let one of us off. Most of us were in tears. He said to carry on and that if we got through that day we would find the real thing easy. We were really angry that we could not come off."

The group had been training for the Ten Tors challenge, a gruelling hike organised by the British army, when they were faced with crossing the swollen Wallabrook stream. There was an island a metre into the four-metre-wide stream and they all had to reach it and then jump to the other side. Yasmin said: "We met two men who told us we had to cross the river to meet the teacher. I thought it was crazy because all I could see was white water and I estimated it to be about three metres deep. There was water rushing everywhere."

She said most of the group managed to cross the stream with help from the two men but then Charlotte was left on the island. "I was scrambling up the bank on the other side when I heard the man say to Charlotte: 'Chuck me the bag'. She didn't scream or panic or anything. She had it with both hands but it went into the water and she went in with it."

Charlotte, a pupil at Edgehill College in Bideford, north Devon, was carried 150m downstream and held under water by the force of the current. Emergency services arrived and Charlotte, from Torrington, Devon, was airlifted to Derriford Hospital but later died. A post-mortem examination found the cause of Charlotte's death to be cardiac arrest due to drowning, Devon coroner's court was told.

The inquest hearing, in Exeter, is expected to run until 22 December.