The number of serious incidents reported by an under-fire ambulance service so far this year has doubled on the same period in 2013.
The East of England Ambulance Service Trust was attacked by MPs after a series of shocking failures.
In a bid to improve response times it launched a recruitment drive for new paramedics.
But trust board papers show there have already been 36 serious incidents reported in the first four months of 2014 - compared to 17 between January and April 2013.
Of the 36 incidents this year an alarming 22 involve the death of patients.
The nature of the serious incidents include ambulance breakdowns, response delays, an incorrect address, equipment failure and clinical treatment.
Health minister Dr Dan Poulter described the incidents as “unacceptably poor standards of care”.
He said: “As a doctor I know there are very complex reasons sometimes for why things go wrong.
“We have to look at each case individually but clearly there are a number of incidents here resulting in unacceptably poor standards of care for patients.
“I know we have some incredibly dedicated, hardworking, highly skilled paramedics and I would be surprised if it was a direct error from them that led to a serious incident.”
An East of England Ambulance Service spokesman said: “Recently we have put a variety of processes in place to help identify serious incidents to ensure that they are fully investigated.
“We always encourage staff to flag any issues they have and each serious incident is thoroughly examined and reported externally, and measures put into place to help prevent such incidents happening again.
“We are actively taking measures to help reduce the number of serious incidents by recruiting 400 student paramedics and putting more ambulances out on the road.
“When serious incidents do happen it is important to look into them thoroughly to understand why they happened and what actions can be taken in order to prevent them happening again.
“With each serious incident we are open with the family to inform them of the process and then the findings of the investigation.”
In March last year, three-month-old Bella Hellings died after paramedics took three times the target time to reach her when they got lost twice and stopped to refuel.
The same month another ambulance took two hours to reach a pensioner who had suffered a fall just four miles away from their base.