A sixth-form pupil on a school trip to Ecuador has fallen from an inflatable white water raft and died.
Matthew Hitchman, 17, from the Royal Grammar School in High Wycombe, Buckinghamshire, was on a month-long school trek.
On Sunday he fell off the raft and attempts to rescue him "proved impossible", the school said.
The group from the school had just completed a trek to the Northern Andes when the accident happened.
The pupils had been working on a community project to provide sustainable tourism income in a remote area of Ecuador.
In a statement the school headmaster Philip Wayne said: "Matthew will be sadly missed by all who knew him.
"He was a caring, friendly and well-liked student who was highly regarded by his teachers and fellow pupils."
The school said it had focused on the "safe and compassionate return of 11 boys to the UK without one of their team mates, supporting our staff and students and giving the best possible care we can offer to a devastated family".
A spokesman for World Challenge, which organised the trek, said: "A full independent review is already under way."
He said the firm had suspended white water rafting in all destinations until the completion of the review.
It has been organising educational expeditions for 30 years and claimed that since 2003 more than 6,500 students had completed expeditions to Ecuador.