A 90-year-old woman with a suspected broken hip waited 40 hours for an ambulance and was then left in the vehicle overnight with it parked outside A&E, it is claimed.
Daphne Syms fell on Sunday at her home in St Austell, Cornwall but had to wait until Tuesday afternoon for paramedics to arrive.
After a 17-mile journey to the Royal Cornwall Hospital in Truro, Daphne was left waiting outside in the van due to queues in the accident and emergency department.
Daphne is now awaiting an operation on her hip but her son Steven says his mother could have died had her accident been more serious.
He says the NHS system is “totally broken” and claims that it took nine minutes for his 999 call to be answered.
“We're literally heartbroken to see a 90-year-old woman in such distress, just sat there waiting,” Mr Syms told BBC Radio Cornwall.
“It’s the not-knowing how ill she was or whether she had broken anything. The system is totally broken.
“If that was a cardiac arrest, nine minutes is much too long – it’s the end of somebody’s life. The system is not deteriorating, it’s totally broken and needs to be urgently reviewed.”
Mr Syms also claimed that paramedics are being used to cover nursing shortfalls at Royal Cornwall Hospital rather than concentrating on responding to emergency calls.
A Care Quality Commission report from June warned of “significant work” needed to improve emergency care in Cornwall, where the average wait for category two calls is “around the 200-minute mark”, according to chief executive of the Cornwall Partnership NHS Foundation Trust Debbie Richards.
The Daily Mail reports that the delayed response from paramedics has led to GPs providing urgent treatment in some cases.
A spokesman for the South Western Ambulance Service NHS Foundation Trust told the Telegraph: “We are sorry and upset that we were unable to provide Mr Syms’s mother with the timely response and care that she needed.
“We are working with our partners in the NHS and social care in Cornwall, to do all we can to improve the service that patients receive.”
Category two 999 calls – which include heart attack and stroke patients – should have an average response time of 18 minutes but NHS data for July shows they were over 59 minutes.
The data also showed 29,000 people waited over 12 hours at A&E units in July – up a third from June and four times higher than the NHS target.
A spokesperson for the Cornwall and Isles of Scilly's Integrated Care System told MailOnline: “Like other parts of the country, our health and care system continues to experience pressure.
“The reasons for this are complex, including high demand for primary and secondary care, mental health services and adult social care.”