A total of 57 patients died after having their 999 calls downgraded by an ambulance emergency centre.

An incident report released by the East of England Ambulance Trust, which serves Epping Forest, revealed ambulances were either not sent or arrived late to patients with terminal illnesses who had filled in a Do Not Resuscitate (DNR) form.

The deaths followed 21 of 28 cases where ambulance level of seriousness being downgraded by call centre managers without consultation between December 18 2013 and February 22 2014.

A spokesman for the trust said: "Whether the ambulance took eight minutes or an hour to reach the patient if they had needed resuscitation we would not have been able to provide it."

One family who did not receive an ambulance received a written response from the chief executive and a copy of the final Serious Incident report after making a complaint.

During the two month period, 2,571 patients of downgraded 999 calls required transportation for on-going assessment and treatment.

Chief Executive Anthony Marsh said, “I was told about these changes during a meeting with staff on the 19 February 2014 and immediately launched an investigation and ordered the reversal of the changes.

"Whilst these changes should not have been made in the way that they were, no harm was caused to patients and it had no impact on performance reporting.

"Since I took over we now have much stronger governance arrangements in place, alongside an experienced executive and non executive team.”