The number of patients who attended accident and emergency wards has increased by more than a million in just one year, figures suggest.
The news comes after experts warned that the emergency care system could collapse in six months as a result of rising demand.
Latest data from the Health and Social Care Information Centre show that 18,300,190 people attended A&E units in England between February 2012 and January 2013 - a rise of 1,034,802 from the previous year.
Almost two fifths (39%) of those who were seen by A&E doctors were discharged with no follow up - meaning the patient did not require any further treatment or advice about their condition. The number of patients who were admitted or referred on remained broadly similar, the provisional statistics suggest.
Earlier, the College of Emergency Medicine called for "fundamental change" in the way emergency care is run, warning that A&E units are facing their biggest challenge in more than a decade as departments grapple with "unsustainable workloads" and lack of staff.
And the Foundation Trust Network, which represents more than 200 health trusts in England, warned that A&E services were in danger of collapse in six months' time as a result of "huge pressure".
Health Secretary Jeremy Hunt said changes to the way out-of-hours care is provided had a "huge impact" on the services. Mr Hunt said there was a "dramatic fall in confidence" in evening and weekend non-urgent cover since the last government changed the GP contract in 2004 to remove responsibility for out-of-hours care from family doctors.
"What we need to do is to have a very fundamental look at the way A&E departments work and in particular look at the alternatives to A&E because the Government changed the GP contract in 2004 and they removed responsibility for out-of-hours care from GPs," he told ITV's Daybreak. "That has caused a dramatic fall in confidence in the public in what their alternatives to A&E are - that is what we have to sort out."
In an interview with BBC Breakfast, Mr Hunt said since the contract was changed there were now four million more people visiting A&E departments every year. "I think one of the problems we have at the moment is that it is too difficult to access out-of-hours care," he said. "People don't feel confidence in the care they will get, if they speak to a GP, the GP probably won't be able to see their medical notes and know about their background."
Shadow health minister Jamie Reed said: "It has come to something when A&E doctors issue statements like this. Sadly they are right to warn that A&Es have become 'unsustainable' on David Cameron's watch. These are well-considered warnings from senior A&E staff on the very front line of the NHS. That is why it's worrying when they say England's A&Es are understaffed on every level. Thousands of nursing jobs have been axed since this Government came to power and patients are clearly paying the price with long waits at A&E."