Ministers must take immediate action to 'avert disaster' in A&Es this winter with two-thirds 'unsafe' and almost all woefully unprepared, leading doctors have warned.
Dangerous overcrowding, corridor care and unrelenting demand will create a 'perfect storm' - and current government plans 'won't cut it', the Royal College of Emergency Medicine said.
Emergency departments are already failing to cope after enduring their busiest summer on record and staff are braced for a further onslaught, it added.
The RCEM described the current situation as a 'disgraceful state of affairs' and said it 'beggars belief' that hospitals are going into winter with almost 1,000 fewer beds than last year when an estimated 500 patients died every week due to overcrowding.
Its new survey of 163 doctors in charge of A&Es across the country reveals more than nine in ten (91 per cent) are either 'very' or 'extremely' concerned about the pressure their departments will experience this winter.
Only 3 per cent said they are 'well prepared' for the coming months.
Around two-thirds (65 per cent) said their emergency departments are under more pressure now than they were a year ago and 60 per cent described theirs as 'actively unsafe'.
Almost nine in ten (89 per cent) described current pressure as 'high' or 'very high'.
Emergency departments 'are already failing to cope after enduring their busiest summer on record and staff are braced for a further onslaught' (stock image)
Ian Higginson, president of the RCEM, said: 'We are not managing now and we simply are not ready for winter.
'We have patients scattered all over our departments, many stuck in trolleys or on chairs for hours upon hours.
'The sickest and most injured among them can't get into a hospital bed and end up staying with us, sometimes for days.
'It's a disgraceful state of affairs and I cannot believe it has been allowed to get this bad.
'Patients are dying unnecessarily every week whilst politicians continue to focus on the wrong solutions.'
The results come just days after Health Secretary Yvette Cooper warned the NHS faces a more challenging winter than normal and announced £140million of funding for urgent care in England.
The RCEM welcomed the investment but cautioned the money is 'not being spent in the right places'. It has written to Ms Cooper with suggestions.
Dr Higginson said: 'With year-round pressure hitting departments, the vast majority of us have no spare capacity to help deal with the cold months.
'It was not always this way. Less than a decade ago, the annual NHS 'winter crisis' was declared when waiting times and overcrowding reached a fraction of what we now experience throughout the year.
'We've now got to the point where we can't tell where one crisis ends and the next begins.
'We need governments from all four nations to step up, heed our warning - and act now. Not in a few years, or even a few months - now.
'Existing winter preparations represent the same old same old, and will yield the same disastrous results.
'Our clinical leads agree.
'Knowing that, it beggars belief that we are going into winter with nearly a thousand fewer beds than last year, and with recruitment freezes stopping us recruiting doctors and nurses to help reduce risk for our patients or to get hospitals working.'
The latest NHS England data shows there was an average of 3,310 patients who received corridor care each day in September, with 2,549 in A&E departments and 761 in other hospital areas.
This is up from an average of 2,865 per day in August, made up of 2,297 in emergency departments and 568 in other areas.
Meanwhile, the number of people waiting more than 12 hours in A&E departments in England from a decision to admit to actually being admitted stood at 50,582 in September, up from 44,951 in August.
Dr Den Langhor, emergency medicine lead on the British Medical Association's consultants' committee, said: 'This warning from clinical leads echoes the fears of emergency medicine doctors working across the country as we head into winter.
'Having only just managed the busiest summer on record in emergency departments, we have not yet had time to take a moment to breathe before we face the onslaught of what we expect to be another horrific winter on the frontline.
'These pressures are no longer seasonal - they are continuous.'
Dr Vicky Price, president of the Society for Acute Medicine, said: 'We cannot keep treating predictable pressures as unexpected emergencies.
'What is needed is sufficient staffed hospital capacity, effective discharge pathways and properly supported community and social care services to keep patients moving safely through the system.
'Patients deserve better than another winter of unacceptable waits and care in corridors.'
A Department of Health and Social Care spokesperson said it had been preparing for a challenging winter 'for months', including opening 25 new and upgraded urgent and emergency care units.
They added: 'The Secretary of State has also tasked the NHS with accelerating plans to end corridor care, particularly for children, and for the first winter ever the NHS is publishing corridor care data to shine a light on where pressures are greatest and drive action where it is needed most.
'On top of this, we are expanding access to the flu vaccine and improving GP access through evening, weekend and out-of-hours appointments to reduce pressure on A&Es.'