Record numbers of patients are facing long waits in A&Es as documents leaked to the BBC show the full extent of the winter crisis in the NHS in England.
Nearly a quarter of patients waited longer than four hours in A&E last week, with just one hospital hitting its target.
And huge numbers also faced long waits for a bed when A&E staff admitted them into hospital as emergency cases.
There were more than 18,000 "trolley waits" of four hours or more last week.
That suggests about one in five patients admitted for further treatment endured one of these long waits on trolleys and in hospital corridors - twice the rate normally seen.
Some 485 of them were for more than 12 hours - treble the number seen during the whole of January last year.
The figures come from a document compiled by NHS Improvement, one of the regulators in England, and show that this winter is proving to be the most difficult for more than a decade.
Since the start of December, hospitals have seen only 82.3% of patients who attended A&E within the four-hour target.
That is the worst performance since the target was introduced in 2004.
Chris Hopson, of NHS Providers, which represents hospitals, said what was being seen was not "ordinary winter pressures".
"Trusts are really struggling," he added.
The leaked document also showed:
- Performance started deteriorating markedly in the first week of the new year with 22% of patients waiting longer than four hours to be seen in A&E
- In one hospital - Weston Area - that reached 44%
- Just one trust hit the target of seeing 95% of patients within four hours with only nine within 5% of hitting the mark
- Dangerously high levels of bed occupancy were reported with 94.7% of beds full - well above the "safe" threshold of 85%
It comes after the British Red Cross said over the weekend the NHS was facing a "humanitarian crisis" this winter.
Ministers have denied this is the case, with Health Secretary Jeremy Hunt saying on Monday the health service was coping well given the increasing demands.
But he did suggest the four-hour target may have to be relaxed - it has not been met since July 2015.
He said there were growing numbers of patients attending A&E units with minor conditions and suggested in order to "protect" the four-hour guarantee in the future it may need to be applied only to those with urgent needs.
Dr Kathy McLean, of NHS Improvement, said the data given to the BBC had yet to be verified and was meant for "internal" purposes so the true figure could be lower.
But she accepted that the NHS was facing "exceptionally high" levels of demand.