Heartbroken relatives of a grandmother who died while waiting in a queue of ambulances outside a hospital have demanded an apology from health bosses.

Sonia Powell, was taken to Morriston Hospital’s Accident & Emergency Unit in Swansea, South Wales, on Wednesday afternoon, following a suspected heart attack.

Her family said the 73-year-old had been waiting “at least an hour” by the time she died.

Health officials, who say the wait was in fact around 40 minutes, have now launched an investigation.

Mrs Powell’s granddaughter Kim Thompson said: “We were not happy, she was very, very unwell and should never have been moved from the hospital she was originally at.

“A doctor asked one the paramedics why Sonia had been moved because there was nothing more that could be done at Morriston than could have been at Neath Port Talbot.

“A doctor only arrived five minutes before she died.

“We really want an apology for the way they treated her.”

Mrs Powell arrived at Morriston Hospital at around 3.05pm after being transferred from Neath Port Talbot Hospital.

She was assessed upon arrival, but remained in the ambulance under the care of a doctor and paramedics. Officials said she died at 3.40pm.

Health board Abertawe Bro Morgannwg University could not comment on specific details of the case due to patient confidentiality.

But a joint statement, it and the Welsh Ambulance Service and ABMU said: “The emergency department at Morriston Hospital has been very busy with a high number of ambulances arriving in a short space of time.

“Escalation plans have been activated and staff across the hospital are working closely with colleagues from WAST to keep delays to a minimum.”

Health campaigners said they were extremely concerned to hear about Mrs Powell’s death.

“The board must also ensure no stone is left unturned in this investigation if it is to ensure public confidence remains in its services,” she added.

“I hope what has happened at Morriston turns out to be an isolated case rather than as a result of poor management, but problems that result in the deaths of patients are occurring all-too-often in ABMU hospitals.

“I do not share the health minister’s confidence that the current ABMU board is the right team to see through change and improve standards.”

Mrs Powell’s death came on the very same day the British Medical Association warned the NHS in Wales was facing “imminent meltdown”.

The BMA’s Welsh Council chairman Phil Banfield said an independent inquiry was desperately needed.

He said: “There’s a lot of sticking heads in the sand still going on.

“Our greatest fear is it will become impossible to have an NHS in Wales.”

And in recent months, health officials and the Welsh government have come under scrutiny about ambulance response times.

According to the latest official figures, the Welsh Ambulance Service failed to hit response time targets for the most urgent calls for a ninth consecutive month.

Statistics also showed that 87.7% of people arriving at Welsh A&Es were seen within four hours of arrival - the Welsh government target is 95%.

The worst-performing health board was Abertawe Bro Morgannwg, with nearly 17% of patients waiting more than four hours.

Mrs Powell’s death marked a devastating 24 hours for her family. Earlier that morning, Mrs Powell’s sister Cheryl Davies, 64, died at a local hospice.

ABMU health board has issued a fresh statement regarding Mrs Powell’s death.

A spokeswoman said: “The health board is reviewing all aspects of what happened and we are currently discussing these with the family.

“We can confirm the ambulance with two paramedics on board left Neath Port Talbot Hospital at 2.49pm and arrived at Morriston Hospital at 3.04pm.

“The Emergency Department doctor began his assessment of the patient in the ambulance at 3.07pm.

“A doctor remained with Mrs Powell on the ambulance until she sadly passed away at 3.40pm.”

The spokeswoman added if a patient deteriorated in a “supporting” hospital and could benefit from treatment available at an “acute hospital”, ABMU would arrange for an ambulance to transfer them.

“Yesterday was a busy day for Emergency Departments and this was intensified at Morriston by 20 emergency ambulances arriving and departing within a short space of time,” she continued.

“At its peak, there were 12 operational ambulances outside the department but not all had patients on board.”

ABMU also stressed, upon arrival that all medical emergencies were assessed by a doctor in the Emergency Department to ensure “they receive the most appropriate treatment before being transferred to a bed”.