A six-month-old baby tragically drowned in a hot tub after crawling into the garden through the backdoor.
Eddie Murphy-Boxall made his way outside while his mum was working from home at the property in Worthing, West Sussex, on June 24.
Siobhan Murphy left the door open on the “extremely hot day” and had two hours of conference calls booked.
Eddie and his twin brother were in the downstairs bathroom before the tragedy.
Mel Doyle, the coroner's officer for Crawley, told Crawley Coroner’s Court: "When Siobhan finished her work meeting, she called the boys. Eddie did not come out of the bedroom.
"Siobhan realised the backdoor was open and Eddie must have crawled outside.
"She saw the lid of the hot tub was open. She went to the hot tub and found Eddie in the water, unresponsive."
A member of the public came to assist Mrs Murphy, who called 999 at 12.25pm.
A helicopter air ambulance was scrambled to the family home and Eddie was airlifted to Worthing General Hospital, where he was declared dead just after lunchtime.
Dr Karen Henderson, the assistant coroner for West Sussex, concluded the case was an accident and called it “every parent's worst nightmare”.
Mrs Murphy had often worked at night after her children had gone to bed to fit in her work and child-caring responsibilities, the inquest heard.
Following a post mortem examination, Eddie's cause of death was given as "immersion in water (drowning)" and a police investigation was launched into his death.
Dr Henderson said the report found "there were no concerns of negligence or any risks in terms of the state of the house or the facilities, everything pointed to a loving family that had been left heartbroken and bereft by their loss."
Concluding the inquest, Dr Henderson said on the balance of probabilities she was satisfied that Eddie's death was a "tragic accident" and there were no learning opportunities.
The coroner added: "It is quite clearly a truly heartbreaking situation that Eddie, with his brother, was the most wanted child who had throughout his short life been beautifully cared for and was the most treasured possession. He was all things for their parents.
"It is by far every parent's worst nightmare but it was through a combination of circumstances that sadly led to Eddie's death – that the hot tub lid was not closed as was thought, that they were working from home during Covid and the difficulties of combining that with childcare and indeed it was a very hot day – that this allowed, sadly, Eddie to slip out and to climb into the hot tub.
"I cannot for a minute imagine how difficult this has been for Eddie's parents and for other family and I am so sorry."
A verdict of accidental death was recorded.