The health service will find it difficult to meet treatment targets without increased funding, an NHS executive has said.
NHS England's director for acute care, Prof Keith Willett, said the health service was trying to deal with rising demand.
The comments came after a BBC survey found targets for cancer care, A&E treatment, and planned operations were being routinely missed.
Prof Willett told BBC Radio 4's Today programme: "Depending on the agreements on funding for the NHS in the autumn statement over the next couple of years, it will be difficult for the NHS to continue on the trajectory that we want to set."
Asked if the NHS could get back to its performance levels of four years ago without increased funding, Prof Willett said: "I think that's going to be extremely difficult, but that is our intention."
He added: "We have actually started treatment on 16 million patients in the last 12 months in the NHS. And that's 5% up on previous years.
"And, if we go to the target which is commonly discussed, the four-hour target in A&E, that's absolutely right and proper that we plan to try and get back to the 95% target that's been set, and we are currently achieving the 90%, which is our, sort of, work-to target over the next few years.
"We are improving. We have started to see all the implementations of the things that we have been planning, particularly, in urgent emergency care, starting to have effect in terms of holding that growth in demand."
Prof Willett said that the NHS was highly cost effective compared with health services overseas.