Little children drown "quickly and silently" a bereaved mother who lost her young son told Good Morning Britain.
Lorna Else's son Oliver died in a swimming pool accident in July 2010, aged 2-years-old. Today would have been Oliver's seventh birthday.
Mrs Else, 45, has worked as a consultant on the short film "The Danger Age" which aims to highlight the dangers posed to very young children by baths, ponds and swimming pools.
Oliver's accident took place during a family party at Mrs Else's parents house. The two-year-old had been splashing about in the pool during the day with his brothers and cousins, wearing armbands and a rubber ring.
Mrs Else's husband, Jason, removed the swimming aids when the children went into the pool house to watch a DVD towards the end of the day.
But Oliver crept back outside when no one was looking and got into the pool. When his grandfather spotted him, he was floating face down. Oliver was taken to hospital, but died three days later.
Ms Thomas founded the Child Bereavement Trust, but is now retired and works as a bereavement counsellor for charity The Angus Lawson Memorial Trust, which works to mitigate child suffering around the world. She counsels children who have lost siblings or parents, and helped the Else family after Oliver died.
Mr and Mrs Else live with their three surviving sons, Thomas, 10, Samuel, 5, and two-year-old Alexander in Hitchin, Hertfordshire.
Jenni Thomas, the bereavement councillor behind the safety film, urged parents to "never, ever relax around water with young children".
The film has been been paid for through the fundraising efforts of Simon Martyn, another bereaved parent whose story inspired the film. His son Conwy, aged 3, died in a drowning accident.