The father of a schoolboy who died following a severe allergic reaction said his death "doesn't make any sense", as he told how he watched his son die.
The 13-year-old, named in reports as Karanbir Cheema, was taken ill at William Perkin C of E High School in Greenford, west London, at around 11.30am on June 28.
He was taken to hospital in a life-threatening condition but died with his parents by his side on Sunday.
Karanbir's father Amarjeet told the Evening Standard how he had watched his "brilliant" son die in hospital.
He said: "We were in hospital. I had to watch him die - no parent should have to go through that. While he was in hospital we were fully concentrated on his condition. Now we want answers. How could this have happened?
"My son had allergies but he was very careful. He had an allergy to dairy products but was good at avoiding them. I don't how a piece of cheese hitting him could have killed him, it doesn't make any sense. We have been told very little."
Mr Cheema said his son was an "amazing" student who had talked about being a computer engineer, adding: "We were so proud of him. He had a very bright future. There are a million things he could have done with his life.
"He was a bright, bright boy. He was kind and gentle. We are just devastated."
Police have arrested a 13-year-old boy on suspicion of attempted murder, the Metropolitan Police said.
A post-mortem examination is due to take place on Wednesday.
A statement on the school's website said: "The school community is deeply saddened at the loss of a Year 8 student who died on Sunday July 9 at hospital following a severe allergic reaction.
"Students have been supported at school in the face of this tragic incident and many good wishes have been posted in the school chapel in memory of this popular and well-liked student.
"The school has kept in close contact with the family, particularly in light of a number of unfounded rumours which have circulated over the past days.
"The student in question had always dealt responsibly with his multiple allergies and medical staff were therefore able to respond quickly with his agreed care plan during the incident on Wednesday June 28."