45% of NHS trusts declared major alert last week
Some 45% of NHS trusts in England declared a major alert last week as services came under pressure.
Sixty-eight trusts out of 152 raised the alarm at least once due to bed shortages and problems managing the flow of patients through A&E.
Overall, NHS hospitals issued 294 operational alerts over the week from January 7 to 13, saying they were experiencing major pressures.
Some 27 trusts issued an alert on every single day.
The number of major alerts - previously called red and black alerts - cannot be compared with the previous week because NHS England has changed the way data is recorded.
Between January 9 and 15, there were also 52 occasions when A&E departments closed their doors to new patients - known as A&E diverts.
This compares to 39 the week before, between January 2 and 8.
There were also higher reports of the vomiting bug norovirus than this time last year, while flu cases have not yet reached their peak.
Hospitals have 95.8% of their beds full - up from 94.8% in the previous week and above the 95.2% for the same period last year. Anything above 85% increases the risk to patients from infection.
The data on norovirus shows there have been 3,049 cases in hospitals so far this year. This is 9% higher than the average number over the last five years, and 75% higher than the same period last year.
There have also been 1,305 cases of another bug, rotavirus. This is 21% higher than for the same period from 2013 to 2016.
As a result of the bugs, bed closures on wards have been much higher than last year though they are falling compared to previous weeks this winter.
Across the week, 82 people were admitted to intensive care or high dependency units with flu, while 11 people died from flu, taking the number of deaths this winter to 45.
An NHS England spokeswoman, said: "Demand moderated somewhat last week, but A&E departments remain under pressure, with flu cases set to increase and norovirus still higher than last year.
"As flu increases, we would remind the public that if you're otherwise healthy, usually you can manage flu symptoms yourself at home and there's no need to see a GP. Most people feel better within a week."
Official NHS guidance says a level 3 operational alert is when the local health and social care system "is experiencing major pressures compromising patient flow and continues to increase".
Level 4, the most serious, shows that pressure "continues to escalate, leaving organisations unable to deliver comprehensive care. There is increased potential for patient care and safety to be compromised".
Shadow health secretary Jonathan Ashworth said: "Theresa May's NHS crisis is getting worse by the week. Twenty-seven hospital trusts have warned they are unable to deliver comprehensive care and on average 50 hospitals are calling in extra support every single day.
"The Prime Minister can't keep dismissing this as a 'small number of incidents'. Her response has been derisory and she needs to set out what action she is going to take to make sure patients can access the services they need.
"Labour is calling for urgent investment in social care and a commitment to put the NHS on a long-term sustainable footing in the March Budget to avoid a winter like this again. Quite simply, the Government's policy of underfunding and mismanaging the NHS has left hospitals on the brink."
C hief executive of NHS Providers Chris Hopson said: "These latest figures show the NHS working flat out last week to provide safe and timely care for patients in the midst of unprecedented demand.
"This is reflected by the increase in the number of trusts with A&E diverts which almost doubled compared with the same week last year. Bed occupancy rates have also risen, and remained well above recommended levels to ensure patient safety.
"The number of trusts reporting serious operational pressures was a further cause for concern. Anecdotally, however, trusts have told us that the extreme pressure of the first 16 days of January, reflected in these figures, has now eased over the four days and we expect this to be reflected in next week's figures.
"We should recognise, however, that a flu outbreak or a cold snap still have the potential to immediately reverse this improving position."
Liberal Democrat health spokesman Norman Lamb said: "This NHS winter crisis brings bad news day after day and patients are paying the price.
"The Government are doing nothing to deal with it. I don't know how bad the figures need to get for them to actually take action."