A 74-year-old pensioner died after being to forced to wait 16 hours for an ambulance to arrive at his home, an inquest heard.
Joseph Edge was left lying in agony for hours after his wife Carole dialled 999 when he became unwell at 1.30pm on December 28, 2019.
An inquest heard how paramedics didn't arrive at their home in Llandegla, North Wales, until 5.55am the next day at which point he was "cold and unresponsive."
By then it was too late and the OAP was pronounced dead in the early hours of December 29, 2019.
In the aftermath of his tragedy, police investigated the Welsh Ambulance Service (WAS) for possible corporate manslaughter charges due to the delay.
No further action was taken but an inquest was told how Mr Edge was "denied the right treatment" as a result of call handler blunders which could have saved his life.
The hearing at County Hall in Ruthin, Denbighshire, on Tuesday heard the service had been experiencing "unprecedented" demand at the time.
Emergency vehicles were stranded for six hours outside a hospital as the service received a third more calls than on a usual night.
Mr Edge's widow - married for 52 years to the former plumber and mechanic who had a heart attack at the age of 48 and then suffered a stroke - said he'd been unwell and had a stomach bug.
At 5am on December 28 she heard her husband in the bathroom and he was bleeding from a bang to the head.
Later that morning he complained of feeling dizzy and his blood pressure was very low.
Mrs Edge rang NHS Direct but got no answer so called her surgery.
Mrs Edge was unable to get him out of bed, so they had to wait for an ambulance instead of travelling to hospital themselves.
The pensioner, who had retired early after suffering a heart attack and stroke when aged 48, was placed in the lowest priority green two response category.
But the hearing was told the call operator had mistakenly allocated Mr Edge as a trauma patient when “dizziness” would have been a more suitable allocation.
This would have meant that different clinical questions would have been asked of Mrs Edge, and her husband would have been upgraded to “green three” category.
The inquest was told this wouldn't have made any difference in the response time of the WAS.
Mr Edge was then upgraded to “amber two” after Mrs Edge spoke with a clinician who had called to enquire about the state of Mr Edge's condition.
The clinician deemed the need for an ambulance to be more urgent than a green response due to his low blood pressure.
Gill Pleming, utilisation manager for North Wales at WAS, told the inquest that the service was facing "unprecedented" levels of demand.
She said during the night of December 28 to December 29 they receiving 450 calls instead of 350 in a typical 24-hour period.
There were also people in the category above Mr Edge waiting at the same time meaning he was never next in line.
The hearing was told how 999 ambulance calls coded “red” had an eight-minute response time target but there was no set time for any other category of calls.
All resources were allocated to other incidents or at hospitals, with ambulances at Glan Clwyd Hospital stranded there for six hours while waiting to hand their patients over.
Mrs Edge received numerous “welfare” calls from the ambulance control room during the 16-hour waiting period - the last of which came at about 3.15am on December 29.
Shortly after 5am, Mrs Edge checked on her husband where she found him "cold and unresponsive".
She called 999 again and a rapid response vehicle arrived roughly 20 minutes later.
Mr Edge, a father-of-two and grandfather, was formally pronounced dead at 5.55am.
"Clearly the service I have received isn't acceptable," Mrs Edge said in a statement.
"I am very upset and annoyed about what has happened."
A post-mortem examination undertaken by Home Office pathologist Dr Brian Rogers found that Mr Edge's heart was enlarged and a main artery was blocked.
Dr Rogers said the nature of Mr Edge's heart disease meant that he "could have died at any time".
He added: "A prompter response from the ambulance service may have led to a different outcome but I can't be certain".
Recording a conclusion of natural causes, Elizabeth Dudley-Jones, assistant coroner for North Wales East and Central, said she was satisfied WAS had done all it could on what was simply an "incredibly busy" night.
But she agreed Mr Edge was "denied the right" to treatment which could have potentially saved his life.
She added that "such were the pressures faced by the WAS on that day, they could not get there", which she described as a "tragedy".
Mrs Dudley-Jones said she did not see fit to issue a prevention of future deaths order to the WAS, which has been taking steps to improve its response times.
Claire Roche, the Welsh Ambulance Service's executive director of quality and nursing, said afterwards: "We extend our deepest sympathies to Mr Edge's family at what we know will be a sad and difficult time.
"We acknowledge the coroner's conclusions and sincerely apologise to Mr Edge's family for what we agree was an unacceptable delay.
"We are an organisation committed to learning and will continue to work with the health board to improve our timeliness to respond to people when they need us."
