The full extent of the pressures medical staff are being put under is now clear, with thousands of sick people forced to queue for care as the outbreak of the norovirus and flu stretches workers to the limit.
In the worst reported case a patient had to wait 23 hours, while thousands more are waiting longer than the Government's four-hour target limit.
More than 7000 patients spent in excess of four hours in emergency units between December 23 and January 6. Of those, almost 300 waited more than 12 hours until they were either discharged or admitted to hospital between last December 23 and January 6.
The figures obtained in a snapshot survey of 11 health boards do not take account of predictions by experts that the norovirus bug has still to reach a peak.
A shortage of staffed hospital beds is creating a backlog of patients left on trolleys until they can be transferred.
NHS Lothian, which runs Scotland's busiest emergency unit at Edinburgh Royal Infirmary, was unable to treat more than 1600 patients within the Government's four-hour target while Scotland's largest health board, NHS Greater Glasgow and Clyde, saw 3392 patients exceed that time limit, affecting 13.5% of those treated.
Melanie Hornett, nurse director for NHS Lothian, said her area was "experiencing unprecedented demand".
Jane Grant, chief operating officer for acute hospitals at NHS Greater Glasgow and Clyde, said the Victoria Infirmary in Glasgow had a 12% surge in emergency admissions in December compared to the same month in 2011. NHS Lanarkshire had 152 patients wait more than 12 hours, including one patient who had to wait 23 hours before being transferred to a specialist bed.
A spokesman said it had to cope with a 10% year-on-year rise in emergency admissions and its three main hospitals were under "significant pressure", partly due to norovirus closing wards and making staff sick.
A&E consultant Dr Jason Long, chair of the Scottish board of the College of Emergency Medicine, said it had been the worst winter for hospitals in six or seven years.
Dr Long said patients had waited on trolleys in hospital corridors for 12 hours and beyond in different parts of the country and in some cases beds had been brought in to A&E departments to create mini-wards owing to a lack of space.
He said: "That is not ideal in that we are still having to deal with all the other patients coming in as emergencies. We should get patients to wards in a reasonable time frame, but if there is no bed to go to they will stay in the emergency department.
"Our managers are there late at night and early in the morning trying to do their bit for the patients. There are nurses going way beyond what they would usually do to try to help."
Dr Long and other physicians have met with Health Secretary Alex Neil three times to raise their concerns.
Shadow Health Secretary Jackie Baillie said: "This winter was always going to be difficult with 2500 fewer nurses and midwives employed in our hospitals. But the four-hour target has not been met by the majority of boards in any month for the past two years. We are now going back to the early 1990s, with stories of patients waiting hours to be seen, patients left on trolleys and care standards falling as hard pressed staff struggle to keep up with demand."
Margaret Watt, chairwoman of the Scotland Patients Association said the figures were shocking.
A Scottish Government spokeswoman said the vast majority of patients were still treated within the target time.
She added: "Boards plan for situations like this and we are continuing to work closely with them, including providing an extra £3 million to help manage winter pressures."
On Tuesday, Health Protection Scotland said increased awareness about spreading the norovirus has meant hospitals are experiencing normal activity for the season, despite a large increase in the number of cases