Monica Lewis, a 57-year-old Croydon grandmother, died from a heart attack after an ambulance took more than an hour to reach her on Friday morning.
Lewis, who suffered from epilepsy was having a severe fit when her partner Harry Smith, 73, phoned for emergency medical attention.
Lewis had been classed as a Red Two patient – serious but not immediately life threatening – at 12:29 am, which led to two ambulances in Croydon being diverted to higher priority calls.
Official guidelines state that the ambulance should have taken 19 minutes.
After Smith told the operator that Lewis was still breathing, another two ambulances were diverted to more urgent Red One cases – cardiac arrest or life-threatening traumatic injuries – in the space of 47 minutes.
At 1:16 am the operator upgraded the call from Red Two to Red One, meaning Lewis was now in a life-threatening situation.
The ambulance – which was sent from Brixton, eight miles away – arrived at her house in Croydon at 1.39 am.
National targets state 75 per cent of Red Two calls should be reached within eight minutes. In November 2014 only 55 per cent hit this target in the capital, compared with 68 per cent across England.
Smith told the Daily Mail: “If the ambulance had got here in time, she would have survived. That’s a fact”.
A London Ambulance spokesperson said: “Based on the information provided by the caller, the patient was conscious and breathing”. They added: “We are very sorry that we were unable to send an ambulance any sooner” and offered their sincere condolences.
Monica’s daughter Gemma Senior said: “She only lived a ten-minute drive from hospital”. Adding that she was “disgusted and disappointed” by the failure of the NHS.