NHS England is going to move to its highest alert level from midnight tonight.
The health service's chief executive, Sir Simon Stevens, announced the move to level four was in response to a "serious situation ahead".
There are four incident levels used across the NHS, with level four meaning there is "an incident that requires NHS England National Command and Control to support the NHS response".
Under level four, NHS England will take over coordination of the NHS's response to the incident, in collaboration with local commissioners.
The general public will not see any difference if they use the NHS, but it means the overarching NHS England body has had to take over to ensure all services are supported appropriately.
Sir Simon announced the level was being raised after he said there are "22 hospitals' worth" of coronavirus patients in hospitals in England.
He said there had been a "very substantial" increase in "desperately sick patients in hospitals" in October.
"The facts are clear, we are once again facing a serious situation," he said.
"This is not a situation that anybody wanted to find themselves in, the worst pandemic in a century, but the fact is that the NHS is here.
"The public can help us help you so our fantastic staff - our nurses, our doctors, our paramedics - can get on with looking after you and your family there when you need it."
