NHS leaders have warned that strikes by junior doctors and consultants this week will cause unprecedented disruption for patients, amid a historic joint walkout.
Planned care is likely to come to a halt with thousands of appointments cancelled, as the row with the Government over pay and working conditions continues.
Junior doctors will then continue their strike on Thursday and Friday.
Those dates coincide with the Conservative Party annual conference in Manchester.
Staff are expected to work on a “Christmas Day cover” basis for both spells of industrial action, meaning emergency care will continue to be provided.
Ahead of the strike action, NHS national medical director Professor Sir Stephen Powis warned the health service had “never seen this kind of industrial action in its history”.
He added: “This week’s first ever joint action means almost all planned care will come to a stop and hundreds of thousands of appointments will be postponed, which is incredibly difficult for patients and their families, and poses an enormous challenge for colleagues across the NHS.”
He said people should still call 999 and use A&E as normal in emergency situations.
Rishi Sunak began his premiership pledging to cut waiting lists, but ministers’ failure to resolve the dispute with junior medics and consultants has cast doubt on whether that promise can be achieved.
Figures released earlier this month showed the NHS waiting list in England reached a new record high with 7.7 million people – around one in seven – waiting for treatment.
She warned it is “likely to cause disruption to patient care unlike anything we’ve seen before”.
Ms Cordery added: “We need this dispute to be resolved, and fast, but there is a deep and growing frustration among trust leaders at the sheer lack of action to even start to break this deadlock. We cannot allow strikes to become business as usual for the NHS.
“With no end in sight, trust leaders are once again urging the Government and trade unions to sit down and talk so that everyone’s focus can get back to the real priority: providing safe, high-quality, and timely care for patients.”
A Department of Health and Social Care spokesperson said: “We’ve already seen 900,000 appointments cancelled as a result of strikes and the co-ordinated action next week will create further disruption for patients and fellow NHS staff.
“We accepted the independent pay review body’s recommendations in full, meaning doctors who started their hospital training this year are receiving a 10.3% pay increase, with the average junior doctor getting 8.8%. Consultants are receiving a 6% pay rise and are already in the top 2% of earners in the country.
“This pay award is final and the Health and Social Care Secretary is clear his door is open to discuss non pay issues if the BMA call an end to this damaging disruption.”