The family of a boy killed by a falling tree branch on a school trip say it was a one-in-a-million chance accident.
Daniel Mullinger, 11, from Stanway, near Colchester, Essex, died and three children were injured in Tuesday's accident at Felbrigg, in Norfolk.
They were among nearly 60 children from Heathlands Primary School in West Bergholt near Colchester, Essex.
Daniel's grandfather, Cliff Mullinger, 70, said he hoped the death would not stop other children going on trips.
The pupils were on a five-day break at Aylmerton Field Study Centre in Aylmerton, Norfolk.
The accident happened in the grounds of Felbrigg Hall, a manor and estate owned by the National Trust.
Mr Mullinger said: "The branch could have fallen on absolutely anyone.
"He was really looking forward to this trip. It's a one in a million chance of this sort of thing happening and you can't stop it.
"I hate to think other children would be stopped going on trips like this because of what has happened.
"You can't blame the teachers. They must be absolutely distraught. They were there when it happened and I can't imagine how they must feel."
Mr Mullinger said the family was supporting Daniel's parents, Stephen and Wendy, both 39, and helping to look after Daniel's eight-year-old sister, Lucy.
An 11-year old boy is in a critical but stable condition in hospital with pelvic and internal injuries, while an 11-year-old girl is in a comfortable condition after suffering leg and arm injuries.
A 10-year-old boy also suffered a wrist injury.
The remaining children on the trip have returned home.
Hilda Mullinger, 67, Daniel's grandmother, said the boy critically injured in the accident was Daniel's best friend.
Head teacher John Watts said: "We are devastated. Our thoughts and prayers are with the families of the little boy who died and the two boys and girl injured."
Norfolk Police and the Health and Safety Executive are carrying out investigations.