Dr Salwa Malik said a lack of social care capacity for those ready to be discharged was causing fatal delays in A&E.
Her shocking frontline account reveals that, in some hospitals, it has become the norm to have tens of patients waiting on trolleys in corridors.
Doctors feel under pressure to raise the bar for admissions by sending home people who would usually stay, she said.
And even the most experienced staff who are “used to the hard grift and chaos” of A&E are terrified of making mistakes and losing their licence.
Dr Malik said: “Something needs to happen. In two or three months, it’s scary to think of what it could look like.
“The numbers of deaths are not going to come down, it’s only going to get worse unless something happens – and we don’t want to see patients die.”
Speaking in her role as a vice president of the Royal College of Emergency Medicine (RCEM), Dr Malik laid bare the horrific scenes unfolding as the health service nears breaking point.
When she qualified as a junior doctor in 2009, 12 hour A&E waits were virtually unheard of and patients breaching four hours would cause a “massive stink”.
Lengthy delays are now common. In November, almost 38,000 patients in England waited over 12 hours to be admitted after a decision to admit, and 144,000 waited more than four hours.
On Christmas Day alone, ambulances wasted more than 3,600 hours waiting to offload patients at hospitals. Some 1,647 handovers took over an hour.
Dr Malik said: “The other day there was a patient who had been waiting in the department for three days who ended up having a cardiac arrest and died.
“There have been patients unfortunately waiting for NHS 111 to pick up the phone for over an hour, then deteriorating and it being too late by the time they come to us and they have passed away.”
The RCEM estimates that delays to emergency care are causing 300 to 500 deaths per week.
Dr Malik described how doctors are also having to raise the bar for admissions and lower it for discharges, sending home patients who would usually be expected to stay in hospital for a few more days.
This means making decisions “you know in your heart probably aren’t the best”.
She explained: “When you’re being told, ‘try and see if there’s anyone that you can get home’, you end up trying to adapt your thinking, maybe taking a slight risk.
“Sometimes you get it wrong. You send them home and they end up coming back more unwell.”
The last two years had already felt like a “forever winter” thanks to the pandemic, then the real winter arrived in November.
Rising Covid cases, high flu rates and an increase in demand from patients who put off seeking NHS care during the last two years have all exacerbated seasonal pressures.
Dr Malik, who works in East Sussex, said trollies were piling up in corridors. Patients are being robbed of their dignity as they wait to be moved to a ward, without easy access to a toilet or call bell, she said
She added: “We’re now seeing over 30 to 35 patients in our corridor at any one time 24/7.
“They’re no longer waiting a day within the emergency department, it’s now three days. Last week we had so many patients requiring oxygen in the corridor that we ran out of cylinders. An emergency supply was delivered.
“Another new thing is physically having no beds at all. If you had more people coming in there was no bed or trolley to actually put them on.”
Meanwhile, around 12,000 medically fit patients are stuck in hospitals in England, unable to leave as they are waiting for a care home space or home support.
The Government allocated an extra £7.5 billion for social care and £6.6 billion for the NHS over the next two years to tackle the issue.
But Dr Malik said the impact was not being felt. She urged ministers to launch a social care recruitment drive and do “whatever it takes” to grow capacity.
Once the flow through hospitals is improved, other challenges such as filling NHS vacancies should be addressed, she said.
She added: “If you unplug that exit block, all of a sudden all these things the NHS is putting in place at the moment will work really well.
“Then the waiting lists will come down, people can get on with their surgery. So actually the answer to all of this is social care.
“This is the worst we’ve ever known it. The foundation cracks started 10 years ago and have been getting worse, and now it’s gone all the way through and people are falling through those cracks.”
A Department of Health and Social Care spokesperson said: “We recognise the pressures the NHS is facing following the impact of the pandemic and are working tirelessly to ensure people get the care they need, backed by up to £14.1 billion additional funding for health and social care over the next two years.
“This includes investing an additional £500 million to speed up the safe discharge of patients from hospital, creating the equivalent of 7,000 more beds nationally and establishing 24/7 data driven system control centres in every local area to manage demand and capacity.”