A three-year-old boy drowned in his grandparents' swimming pool after his parents thought he was playfully hiding from them.
Alfie Hayward had been unsupervised for just 10 minutes before his mum found him face down in the six-foot deep pool.
Distraught Lauren Pither told an inquest she thought he had just been hiding in order to jump out and surprise her.
Ms Pither said that on August 18, 2012 she went with Alfie to her parents' house in Ardleigh on the way to Great Yarmouth for a camping holiday.
She went into the house with her sister, while her parents left to pick up a camper van and Alfie played in the front yard.
She said: "I told him to stay in the front, I did not want him going around the back."
But when she came back out the boy had disappeared.
Ms Pither said: "We started looking for Alfie, he was missing 10 minutes at most. He had gone around the back."
She thought he might be hiding behind a bush in order to jump out at her, which he had done previously, but then found him face down in the swimming pool.
There was also a chair, a rock and a rubber ring in the pool, leading Ms Pither to believe that her son had climbed on the chair to throw the rock in before falling into the water.
She told the hearing: "It is what I know my son would do."
Alfie was taken to Colchester General Hospital, where he was pronounced dead, and a post-mortem examination found that he had died from immersion.
Inspector Lynne Corder, from Essex Police, told the inquest there were no suspicious circumstances.
Coroner Caroline Beasley-Murray said: "It was a tragic accident - I am sure you are all going over and over it in your minds and saying 'What if?'
"He was probably a lovely little boy with a bright future ahead of him, and I would like to express the court's condolences to all of you."
The coroner in Chelmsford, Essex, recorded a verdict of accidental death.