NHS 111 will be the new "front door" for Accident and Emergency in order to prevent the NHS from being overwhelmed this winter, Matt Hancock, the Health Secretary has said.
Patients will be told to book appointments at casualty units in advance using the website and phone line in a bid to reduce the pressures on hospitals. They will be instructed to use the service as the "first point of call" for urgent medical care unless their situation is life-threatening.
A public communications campaign, called "Help Us Help You", will be launched later this year to direct people to the correct NHS service.
People will not be turned away if they go to A&E without contacting NHS 111, but will be warned that they may have to wait longer than other patients with similar health problems who had booked in via the 111 service.
Pilot schemes are being rolled out in Cornwall, Portsmouth, Hampshire, Blackpool and Warrington, and will be introduced in every hospital in the country by December using the model found to work best.
Mr Hancock said: "During the peak of the pandemic, we saw millions of people using NHS 111 to get the best possible advice on Covid-19 and other urgent NHS services.
"These pilots will build on this and test whether we can deliver quicker access to the right care, provide a better service for the public and ensure our dedicated NHS staff aren't overwhelmed."
People considering going to A&E will be asked to use 111, with those considered to need hospital care given a timeslot to attend and others directed to the best place for treatment.
Officials said the plans aimed to expand on the growing part played by the 111 service during the peak of the pandemic.
However, some medics have raised concerns that the reforms could create deadly obstacles for those in need of urgent care.
The President of the Royal College of Emergency Medicine has said A&E appointments will help prevent overcrowding when the NHS is attempting to maintain social distancing. Dr Katherine Henderson said it would cause "enormous harm" to patients if Britain returned to crowded casualty units.
Ministers will also announce an extra £150 million to expand and upgrade A&E departments in 25 hospitals to help ensure they have the physical space to treat patients, manage patient flow and improve infection control.
Health officials had drawn up plans to axe the four-hour A&E target and replace it with a more complex set of performance measures, but those proposals have been put on hold and will not be launched without further consultation, which starts in December.