A baby girl died after ambulance crews took 26 minutes to travel one mile to reach her.
Coroner William Armstrong said Bella Hellings could have been alive today had one ambulance crew not got lost and a second not stopped to get petrol.
He added: "'There was a catalogue of catastrophes and a chaotic response."
Paramedics said they couldn't find the house in Thetford, Norfolk, because 'there were too many blue doors', while the other crew made the stop having not been told an air ambulance was on its way.
Three-month-old Bella died at hospital after she suffered a fit and stopped breathing at her home in Thetford, Norfolk.
Paramedics took 26 minutes - more than three times longer than national targets dictate - to arrive. The coroner concluded the baby girl died from congenital heart disease after delays in medical assistance reduced her chances of survival.
Recording a narrative verdict, Mr Armstrong criticised the delays. He said: "By anyone's standard this was a grave emergency - what happened here was a long, long way from the eight minute response target.
"It is a fact that the prospect of a child surviving a cardiac arrest are low. Notwithstanding that the chance of resuscitation are improved if attempted immediately.
"The delay in giving Bella the care that she needed was wholly indefensible. There was a catalogue of catastrophes and a chaotic response."
Mr Armstrong described Bella as a 'star which will always shine' adding: "She will never grow up, she will never lose her innocence, she will always be loved."
After the inquest the East of England Ambulance Trust apologised for the delays and said steps had been taken to avoid future tragedies.
But Bella's parents, Amy Carter and Scott Hellings, said they were considering civil action against the trust.
They said: "We will always believe in our hearts that Bella was let down by the health services when she was at her most vulnerable and when she needed help the most."
John Martin, interim director of clinical quality at the East of England Ambulance Service NHS Trust, said: "I would like to express my condolences to the family. The trust's response to Bella was delayed for a number of factors, primarily the difficulty in locating the address due to it being a new build. "
As a result, a number of specific measures have now been put in place, and the trust has raised the problems of the delay in new buildings and developments appearing on maps and sat nav systems on a national level. "In addition, the trust is recruiting more frontline staff and getting more ambulances on the road in order to improve our service for patients."
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