Next week’s doctors’ strike poses a “catastrophic risk” to patients, health chiefs say.
Up to half the junior doctors in England could to be absent for four days from Tuesday.
A quarter of a million appointments are expected to be axed.
In last month’s strike consultants and nurses covered shifts but many are now on holiday.
Dr Layla McCay of the NHS Confederation, said: “Health leaders are bracing themselves with many aspects of patient care on a knife edge. “The NHS will be open for business but not business as usual.”
One health leader said “patient safety will be compromised” with A&Es likely to be “utterly overwhelmed”. Another warned that, combined with Easter and knock-on effects, hospitals face a “catastrophic risk” over 11 days.

They added: “Consultants who covered last time are now owed time in lieu. Also, the next strike falls over Easter when a lot of consultants have booked leave.”
Medical demand usually soars at Easter. Last year calls to NHS 111 were up 37%.
Doctors want a 35% rise, claiming pay is down 26% in real terms.The Government calls it unreasonable and unaffordable.Yesterday doctors’ leaders said the strike could still be called off.
The onus was on the Health Secretary to table a credible offer.
However, they added: “The clock is ticking.”