The patient’s daughter, who did not want to be identified, arrived at her father’s home in southeast London before the ambulance and delivered CPR for about 10 minutes after he stopped breathing.
A 70-year-old man died of a suspected heart attack after an ambulance took almost 70 minutes to respond to his daughter’s 999 call.
The London Ambulance Service is now investigating its response to the incident on 1 November, which took more than 50 minutes longer than the target average for such cases.
His other daughter, who also asked not to be named, said they wanted to highlight the incident to ensure “no one else goes through this trauma”.
“The emotional trauma of witnessing this and desperately trying to save his life, knowing he was seriously let down, is overwhelming,” she said.
“His last words to the daughter who called emergency services was that ‘this is the most excruciating pain I’ve ever had’ and she now has to live with that.
“Nothing will bring him back but we will do all we can to make sure no-one else loses their life unnecessarily and no-one else goes through this trauma.”
Ambulances in England aim to respond to category 2 calls, such as major burns, epilepsy and strokes, in an average time of 18 minutes.
Emergency targets dictate that 90 per cent of such calls should be responded to within 40 minutes.
The incident comes amid record ambulance delays.
The latest data from October shows an average response time to such calls of 53 minutes and 54 seconds, up from 45 minutes and 30 seconds in September.
The man himself made the first 999 call, also informing his children of his condition, and his daughter arrived from her home approximately two miles away shortly afterwards.
The daughters made several further emergency calls, in which they said they were told an ambulance would be with them “within 41 minutes from the first call”.
He stopped breathing an hour after 999 was first called, at which point another emergency call was made while his daughter gave him further CPR and the incident was redefined as Category 1 for the most serious incidents.
An ambulance then arrived shortly afterwards, 69 minutes after the first call was made.
A London Ambulance Service spokesperson said: “Our thoughts are with the patient’s family and friends during this difficult time and we send them our deepest condolences.
“We are looking into how we responded to the patient, and would encourage the family to reach out to our patient experiences team so we can support them in reviewing what happened.”
