Ambulances at A&E
Ambulances park outside the Accident and Emergency ward at St Thomas' Hospital, London. Dan Kitwood/Getty Images

A patient 'froze to death' after a 16-hour wait for an ambulance, a leaked NHS document has revealed.

The incident, which happened in Suffolk in December last year, came to light following a review of 40 deaths in the area by the East of England ambulance service . The dossier, which was seen by the Health Service Journal (HSJ), claims that staff are overwhelmed by growing pressures on its services.

Other cases reviewed by the dossier outline how one patient waited more than 13 hours after suffering a fall, while another elderly patient died after enduring a seven-hour wait for help following cardiac arrest.

Labour said the allegations were "shocking and tragic," and has called for a full inquiry.

The review comes as the NHS braces itself for the worst winter crisis since the 2010 swine flu pandemic. Doctors have warned that intensive care units are operating at close to full capacity and they regularly have no spare beds to treat gravely ill patients.

English hospitals have been at 100% occupancy on 1,137 occasions so far year this and figures obtained by The Independent show critical care units typically operate at 85% capacity.

"The pressures in critical care are intense across the board," said Dr Gary Masterson, president of the Intensive Care Society. "This is a bad winter, it's the worst since 2010 when we had the H1N1 outbreak."

"The national figures don't always tell the truth, they give an overall percentage, but lots of individual units are running very, very busy at the moment," he told The Independent.

Critics say ongoing cuts to the NHS social care budget have heaped pressure on hospitals and emergency services across the UK.

"If we could get our patients out we could function well but it affects us because social care is so underfunded", Masterson said.