A grandmother who thought she was having a heart attack was forced to wait more than half an hour for paramedics to arrive.
Sue Elsie, of Tuxford Close, Borehamwood, began having severe chest pains and difficulty breathing - so called her friend who immediately dialed 999.
But less than 30 later, as Mrs Elsie lay shaking on the couch, there was no sign of the ambulance and she began fearing for her life.
The 61-year-old is classed as a high risk patient as she suffers from diabetes and lung disease chronic obstructive pulmonary disease.
She said: “It began as sharp pains going through the middle of my shoulder blades and my fingers were tingling.
“With every minute that went past and the ambulance still hadn’t arrived I thought I was going to die. It was a terrifying feeling.
“I was in agony and I knew there was something wrong. I couldn’t stop shaking but I don’t remember much of it as I was really spaced out.”
The first responder finally arrived 40 minutes later and began strapping her to oxygen tanks and blood pressure monitor.
She began feeling “livelier” after having oxygen but the paramedic insisted on taking her to hospital to check her heart.
But it took a further hour for the ambulance to come and she began feeling unwell as and panicked as time went on.
After she was taken to Barnet General Hospital and diagnosed with a chest infection, she was eventually sent home at 4.30am.
Her friend, Karen, who also acts as her carer and was present during the time of the ordeal, has complained about the service received to Hertsmere MP James Clappison.
Mrs Elsie added: “I’ve lost all faith in the ambulance service now. If I had been having a heart attack it would have cost me my life.
“I’ll get a taxi to the hospital in future because next time I might not be so lucky.
“It is a person’s life we are talking about, and it’s such a dangerous thing to be toying with.”
The East of England Ambulance Service said in a statement the first responder which was on its way to treat Mrs Elsie broke down moments before arriving at her house.
It added: “We were called at 7.39pm, a rapid response vehicle arrived to treat Susan at 8.22pm, they found that Susan’s condition was thankfully not as serious as first thought so after a 20-minute assessment, called for back-up and an ambulance arrived at 9.13pm.
“We are sorry that it took us so long to get help to Susan but we are pleased to hear that she is recovering well from her chest infection.
“It was desperately unfortunate that an ambulance, on its way on blue lights, broke down moments from attending to Susan.”
The service is replacing 120 old ambulances across the East of England by the end of April.