Doctors' leaders are warning that operations may have to be cancelled because of the chaos over the appointment of junior doctors.
Consultants will be staggering their leave at Hillingdon
But ministers are confident that this will not happen. One NHS trust outlines how it is planning to keep the wards running.
Hillingdon NHS Trust, in north London, has found it a challenge to fill its junior doctor posts.
On 1 August, 120 junior doctors will be starting new training jobs.
This is twice the number compared to last year. This year, the Modernising Medical Careers programme has removed the staggered appointments system that operated previously.
Earlier this month, board papers from the trust revealed that 15 posts - over one in 10 of the positions up for grabs - had not been filled.
But thanks to a round of eleventh-hour interviews that figure is now down to four.
A spokesman for the trust, which runs two hospitals covering a population of 300,000 people, said: "We would expect those to be filled very soon. We are looking at them at the moment.
"It has been a challenging process, but patient care will not be compromised."
The trust does have the option of filling the four unfilled posts with temporary appointments, but officials have decided not to do that.
The British Medical Association has warned that unfilled posts will lead to cancelled operations, but Hillingdon says that will not happen.
The spokesman added: "Consultants are staggering their leave and nurses will be there to give support, but it certainly will not mean any cancelled operations.
"At the most there may be a slight reduction in the number of outpatient appointments. But I think patients can rest assured that care will be up to the normal standard.
"This is something we have to deal with every year and there is never a problem. It is on a slightly larger scale this year, but that is all."