Their comments came ahead of walkouts planned for Thursday and December 20, plus a strike by English and Welsh ambulance staff on December 21.
The action could mean up to 15,000 operations could be cancelled this week alone. But experts believe it is also a time when the number of patients in hospital with respiratory viruses is set to top pandemic levels.
Analysis of UK Health Security Agency data predicts about 15,660 admissions for Covid and flu from December 8 to 21, compared with 11,482 during the same period last year.
Professor Carl Heneghan, an urgent care GP and director of Oxford University’s Centre for Evidence-Based Medicine, said: “I am supportive of nurses and their issues.
But the health service is in such dire straits that to pull the plug now will be devastating. It’s like switching off the electricity or gas in mid-winter just when you need it most and it will have a severe impact on the public and patients”.
“I could not envisage a worse time to withdraw my labour”. Added to this, we will have illness and deaths linked to cold and poverty. It is the perfect storm.”
Prof Heneghan warned thousands of extra hospital beds are needed urgently, when current occupancy rates stand at 95 per cent capacity.
He said: “I work out we are roughly two weeks from the crisis point when the deluge of respiratory infections takes off and we will be in real trouble.”
Dr Malcolm Kendrick, a GP based in Macclesfield, Cheshire, said: “We are heading for a slow-motion disaster.”
“The whole NHS system is running broken. It functions because it gets £150billion a year but it’s getting worse.”
“Only yesterday, a guy collapsed with a heart problem while I was at lunch. I was on the phone to 999 to get him an ambulance. But there were none so I had to take him in my car to A&E.”
He added: “This is happening all over the country. Why are there no Cobra meetings? Why isn’t the Government rushing round trying to fix this crisis?”
The Royal College of Emergency Medicine says lack of timely emergency care is behind the deaths of hundreds of urgent care patients each week.
Chairman Dr Adrian Boyle said: “I am worried it will become normal for someone to wait an unacceptable six hours on the floor for an ambulance. This should not be normal.”
Health Secretary Steve Barclay has said of the strikes: “NHS workers do an incredible job caring for our loved ones. It is disappointing some will take industrial action ahead of a challenging winter.
“The economic circumstances mean unions’ demands are not affordable. Each additional one percent pay rise for all staff on the Agenda for Change contract would cost around £700million a year.
“Our priority is to ensure emergency services continue to operate for those who need it and limit disruption.”