PROF KAILASH CHAND OBE, 73, would have "almost certainly survived" if an ambulance had arrived earlier, his son has claimed.
The former leader of the British Medical Association, died after suffering a cardiac arrest in July.
Prof Chand, who lived in Didsbury, after his death, was paid rich tributes by former Labour party leader Jeremy Corbyn and Greater Manchester mayor Andy Burnham.
His son Dr Aseem Malhotra says it took more than 30 minutes for the ambulance to arrive, delayed more than four times of the NHS target.
North West Ambulance Service (NWAS) said it was investigating the incident.
NHS England's national target for responding to 999 calls for people with life-threatening injuries and illnesses is seven minutes.
"The ambulance did not turn up for over 30 minutes [and] by the time they did and they [paramedics] attached the cardiac monitor to dad I could see it was a flat line," cardiologist Dr Malhotra was quoted as saying.
He later discovered that it was a "widespread problem" across the country when it came to emergency response time.
Dr Malhotra said: "The government were aware ambulances were not able to meet targets because of staff shortages and increasing demand but they chose not to tell the public about it."
He criticised the government and added the decision to withhold the information was "appalling" and "shows a complete lack of accountability and transparency".
He told BBC North West Tonight had he known about ambulance delays he would have asked a neighbour to take his father to hospital "straight away without waiting for an ambulance".
"I'm almost certain he would have survived," he said.
"I am personally holding the government directly responsible for the death of my father and I am already considering taking legal action against the government for this."
A NWAS spokesperson said: "We offer our sincere condolences to Dr Malhotra and his family and can confirm that we have received a formal complaint from him.
"We are investigating the incident and will liaise with the family to discuss the matter further."
Bob Blackman MP speaks during the event
Pope Francis greets Narendra Modi on the sidelines of the G7 summit near Bari, Italy, in June last year, as Italian prime minister Giorgia Meloni and then British prime minister Rishi Sunak look on