The NHS in England could be facing one of its most difficult starts to the year since it was founded in 1948, one of its most senior executives has said.
Medical director Sir Stephen Powis warned that a six-day strike planned by junior doctors from Wednesday will have a significant impact on routine care.
Hospitals are also having to deal with rising rates of flu, Covid and other winter infections, he added.
The doctors’ union, the BMA, said patient safety remains a top priority.
If it goes ahead as planned, the latest strike will see the longest continuous stretch of industrial action in the history of the NHS.
Junior doctors make up around half of all doctors working in hospitals.
British Medical Association members will walk out for 144 hours in a row from 07:00 GMT on 3 January until 07:00 on 9 January across all of England.
“Six consecutive days of industrial action comes at one of our busiest periods,” said Sir Stephen.
“The action will not only have an enormous impact on planned care, but comes on top of a host of seasonal pressures such as Covid, flu, and staff absences due to sickness – all of which is impacting on how patients flow through hospitals.”
He said there is no doubt that the NHS would be starting 2024 “on the back foot” with the knock-on effects of the strike likely to be felt for weeks as services recover.
Patients are being urged to continue to call 999 and use A&E in life-threatening emergencies, with cover provided by more senior consultant doctors on strike days.
But some services will have to close. Cheltenham hospital, for example, is directing anyone needing emergency treatment to Gloucestershire Royal, which is run by the same NHS trust.
The strike is also likely to have a significant impact on routine care – from outpatient appointments to elective surgery such as hip replacements and some cancer operations.
The most recent action by junior doctors, a shorter three-day walkout before Christmas, saw 88,000 NHS appointments cancelled across England.
An organisation representing large NHS trusts said on Monday that any hopes the strikes could be called off appeared to be fading.
Matthew Taylor, chief executive of the NHS Confederation, told the BBC that industrial action would leave the health service “skating on very thin ice”.
“Unfortunately it feels like there is a stand-off which is the government is refusing to enter negotiations unless the junior doctors call off the strike action, and the junior doctors are refusing to call off strike action unless the government commits to investing more money – and that is a pity,” he said.
The BMA has been pushing for junior doctors to get a 35% pay rise, which it says would restore their earnings after inflation to 2008 levels, but the government says this is unaffordable.
Dr Rob Laurenson and Dr Vivek Trivedi, co-chairs of the BMA’s junior doctors committee, said: “It’s incredibly disappointing that we’ve had to call this strike – no doctor ever wants to have to take industrial action.
“We would still, at this late hour, encourage the government to put forward a credible offer so that we can stop this strike and get back to doing what we really want to do – care for patients.”
The union said patient safety was its top priority at all times and it had plans in place with NHS trusts to constantly review staffing levels and bring striking doctors back to work in an emergency.
A spokesman for the Department of Health and Social Care said: “We urge the BMA junior doctors committee to call off their strikes and come back to the negotiating table so we can find a fair and reasonable solution, and so we can all get back to focusing on patients and their care.
“We know how distressing it is for patients who have had appointments and procedures cancelled, and we have provided £800m to ensure patients continue to receive the highest quality care this winter and ease pressure on hospitals impacted by industrial action.”
BBC News – Home Junior doctors NHS chief tough new year fresh strike looms