NHS England has warned the health service is facing a "worst case scenario" December with a surge of "super flu".
The warning comes as new figures revealed the number of people in hospital with flu have increased by more than half in just one week.
Catch up as it happened: NHS warns of 'worst-case scenario' as 'super flu' surges
Latest figures show:
• An average of 2,660 patients were in hospital per day with flu last week
• This is the highest ever for this time of year and up 55% on last week
• At this point last year the number stood at 1,861 patients, while in 2023 it was just 402
Health service bosses are warning the number of flu patients in hospital has already increased sharply since the week covered by this data - with no peak in sight.
Read more: Why is flu season worse this year?
Virus outbreaks coincide with doctors' strikes
Weekly flu numbers in England peaked at 5,408 patients last winter and reached 5,441 over the winter of 2022/23, the highest level since the pandemic.
Alongside rocketing flu, the number of norovirus patients in hospital has also risen by 35%.
The NHS is now warning winter viruses are starting to "engulf hospitals".
Demand for A&Es and ambulance services is also soaring.
New monthly figures show A&E attendances were a record for November at 2.35 million - more than 30,000 higher than November 2024.
In addition, there were 48,814 more ambulance incidents (802,525) compared with last year (753,711).
Some hospitals across the country have asked staff, patients and visitors to wear face masks to cut the spread of flu, while others have gone in and out of critical incident status due to the high number of people attending A&E.
The record-breaking demand on the NHS coincides with a resident doctors' strike from 17 to 22 December over pay and jobs - sparking fears of major disruption for patients in the run up to Christmas.
People are being advised to attend any planned appointments scheduled during the strikes unless they have been contacted to reschedule.
Flu vaccinations on the up... who can get one?
The NHS is urging anyone eligible to get their flu vaccination to help prevent them getting seriously ill.
Latest figures show more than 17.4 million people have been vaccinated so far this year, more than 381,000 higher than last year.
You can get it if you:
• Are 65 or over in England, Wales and Northern Ireland
• Are 50 or over in Scotland
• Are pregnant
• Live in a care home
• Are the main carer for an older or disabled person, or receive carer's allowance
• Live with someone who has a weakened immune system
• Are a frontline health and social care worker
• Are of school age
• Have certain medical conditions (the NHS has a full list)
Wes Streeting, the health secretary, warned of a "tidal wave of flu tearing through our hospitals".
"We are working with the NHS to make sure it is able to cope with this as best as possible," he said.
Warning 'extremely challenging few weeks ahead'
Professor Meghana Pandit, NHS national medical director, warned the health service faces "an extremely challenging few weeks ahead" with "staff being pushed to the limit".
She said: "With record demand for A&E and ambulances and an impending resident doctors' strike, this unprecedented wave of super flu is leaving the NHS facing a worst-case scenario for this time of year - with staff being pushed to the limit to keep providing the best possible care for patients.
"The numbers of patients in hospital with flu is extremely high for this time of year. Even worse, it continues to rise and the peak is not in sight yet, so the NHS faces an extremely challenging few weeks ahead."
She added: "We have prepared earlier for winter than ever before, and stress-tested services to ensure people have a range of ways to get the help they need and avoid needing to go to A&E.
"For non-life-threatening care, people should call NHS 111 or use 111 online, which can direct you to the most appropriate place, and use A&E and 999 for life threatening conditions and serious injuries."
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Mr Streeting has offered the British Medical Association (BMA) a last-minute deal in the hope doctors will call off the walkout, which starts next Wednesday.
The doctors' union has agreed to put the offer to members over the coming day, and is expected to announced a decision on Monday, just two days before the planned strike.
The offer includes a fast expansion of specialist training posts as well as covering out-of-pocket expenses such as exam fees, but does not include extra pay.
(c) Sky News 2025: NHS facing 'worst case scenario' December amid 'super flu' surge
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