A 12-year-old girl died after landing head first as she tried to leap off a pommel horse in a PE lesson.
Trevyn Joslin is thought to have caught her foot and was knocked unconscious when she fell on to a safety mat in front of classmates.
Paramedics managed to resuscitate her after her heart stopped during the incident at Taverham High School, near Norwich, last week. But she died after being in a critical condition in hospital for a week.
The year eight pupil was described as 'a sunny girl' and 'always smiling' by headmaster Ron Munson.
He said: "Everybody is deeply saddened and our thoughts are with her family and friends."
Trevyn's parents Hannah, 40, and Derrick, 46, have one other daughter, five-year-old Alesha.
Her aunt, Sara Joslin, 40, from Earls Colne, Essex, said Trevyn was 'an absolute angel'.
She added: "What has happened is so tragic for her mum and dad and little sister."
Police are also investigating the circumstances surrounding the accident.
A spokesman for Norfolk Constabulary said: "Officers are currently conducting enquiries into the circumstances surrounding the death of the girl on behalf of the coroner and in conjunction with the Health and Safety Executive."