Almost 200,000 patients in England waited longer than the NHS target of four hours to be admitted to hospital from accident and emergency departments this winter - the most since records began.
While the percentage of A&E patients treated within the four-hour target improved marginally in February compared to January, the worst month on record, the total number waiting longer in the peak winter months was up 45% year-on-year.
Between December 2016 and the end of February this year, 195,764 patients waited more than four hours to be admitted.
That is up from 134,576 during the same period in 2015-16 and a five-fold increase on the comparable months in 2011-12, when 40,791 waited longer than the target time.
The increase was set out in NHS statistics that reveal the rising demand across all services, and come as nursing union the Royal College of Nursing began canvassing members on whether to take strike action over a below-inflation 1% pay award.
Total emergency admissions to NHS hospitals in England rose to 1.44 million in the winter of 2016-17, and overall attendances at A&E were up 3.1% on the preceding 12-month period.
The number of diagnostic tests and referrals for consultant-led elective care or non-urgent procedures were also all up year-on-year by volume.
The figures do show a marginal improvement in the number of hospital trusts hitting the target, with 87.6% of patients seen within four hours in February compared to 85.1% in January.
The standard of 95% of patients waiting less than four hours across the health service was last met in May 2015.
While seven out of eight cancer targets were met, the key standard of 85% of patients receiving a definitive first treatment within 62 days of diagnosis was missed, with just 79.8% treated in that time.
There was better news in mental health services, with 80.2% of patients treated within two weeks of a first episode of psychosis in February, against a target of 50%.
Delayed transfers of care, sometimes referred to as bed-blocking, were also up in February year-on-year, with 184,855 patients waiting to be discharged into community care.
NHS Providers, which represents hospital trusts, said that for the first time the majority of delays could be attributed to a lack of available social care.
Its head of policy and strategy, Saffron Cordery, said: "We welcomed the additional funding for social care in last month's budget, but it is vital that this money is used effectively to ease pressure on the NHS, and help avoid unnecessary delays for patients."
Commenting on the A&E figures, she added: "During the winter NHS staff responded heroically to unprecedented pressures. But that situation is not sustainable. We must start planning now to ensure we do not face similar or worse problems next winter."