A woman went into cardiac arrest and died in the back of an ambulance which had waited nearly an hour and a half in a hospital car park on Sunday night.

The East of England Ambulance Service vehicle arrived at Addenbrooke's hospital in Cambridge at approximately 9.50pm.

But the A&E department was so full that the vehicle and its patient had to wait in a queue because there were no beds onto which to offload the patient.

At around 11.10pm, having waited for more than an hour and twenty minutes to be unloaded into the hospital for treatment, the patient suffered a cardiac arrest.

Half an hour later the patient was pronounced dead in the back of the ambulance.

The ambulance service has opened a major internal incident at the highest alert level.

A Cambridge University Hospitals NHS Trust spokesperson said: “During an extremely busy night in our Emergency Department, a patient was brought to Addenbrooke’s by ambulance with chest pains.

"They were assessed by a registered nurse on arrival and remained in the ambulance, due to significant pressures on A&E, where they were monitored by paramedics.

"Our Emergency Department staff supported the paramedics when the patient’s condition deteriorated, but sadly they died following a cardiac arrest.

"An investigation has now been launched by CUH and our thoughts are with the family at this very difficult time.”

The hospital is dealing with 360 people a day, higher than pre-Covid demand, and is taking steps to increase it's A&E capacity to cope with demand.

To ensure ambulances can handover patients quickly and respond to other urgent calls, Addenbrooke's has provided a temporary structure at the front of the department where patients can be triaged by a hospital clinician.

In a statement a spokesman for the East of England Ambulance Service NHS Trust said: "Shortly after 8pm on Sunday (Oct 24) we were called to an address in Cambridge following reports of a patient with a serious medical condition.

"Our crews assessed the patient at the scene before transporting the patient to Addenbrookes Hospital.

"Sadly, the patient’s condition deteriorated while being transferred from the ambulance to the hospital and the patient died.

"The Trust has begun an inquiry to see if any lessons can be learned from this incident.

"We would like to extend our deepest sympathies to the patient’s family and would invite them to contact us directly to discuss the case."

A spokesman for Cambridgeshire Police said: "Police were called at 11.59pm on Sunday night to Addenbrooke’s hospital after paramedics made us aware of a female patient who had sadly died in the ambulance while enroute.

"As the death occurred outside of the hospital setting police attended and were able to confirm it as non-suspicious."

Earlier this month a detailed series by our Investigations Unit revealed that the NHS in the east of England is at breaking point.

The death comes after a patient suffered a fatal heart attack in the back of an ambulance after it queued for more than two hours outside an accident and emergency department earlier this month.

The incident at the James Paget Hospital in Norfolk happened days after local NHS services declared a maximum alert due to acute pressures.

Norfolk and Waveney went to Opel 4 the previous week over fears patient care could be compromised. The hospital said the local healthcare system "remains incredibly busy".