At least 100 accident and emergency units will offer reduced levels of service and patients will have to travel further for expert treatment under the biggest shake-up of NHS casualty departments in 40 years.

A new two-tier system of A&E departments is the only way to keep a safe health service which is free at the point of use, officials claim.

Under the system up to 70 of England’s 170 casualty units will be designated as “major emergency centres” which treat the most serious conditions and injuries. The remainder will deal only with less serious injuries.

The plan will also attempt to ease the burden on A&E by keeping patients who do not need emergency treatment away from hospitals.

The reorganisation comes amid fears that this winter will put unprecedented strain on England’s A&E units.

Prof Sir Bruce Keogh, NHS medical director, said the system was under “intense, growing and unsustainable pressure” from an ageing population and high numbers turning to casualty departments because of widespread confusion about where else to go. Under his plans, thousands of patients who suffer heart attacks and strokes will travel further by ambulance in order to access specialist care, which he says cannot be safely provided alongside every casualty unit.

Officials said the remaining A&E units would care for the vast majority of emergencies, such as broken limbs, blackouts and abdominal pain, with the intention that those patients could be seen quicker.

Despite travelling longer distances, patients with more serious conditions, including severely ill children, would receive better care in the new “major emergency centres”.

The changes in NHS urgent and emergency care call for “a fundamental shift in how and where” patients are treated, within three to five years, to relieve pressure on hospitals, amid fears that the system cannot cope with rising demand.

A spokesman for NHS England said: “Bruce Keogh specifically rejected the idea that there would be cuts in accident and emergency departments. His aim was to properly reflect the reality of emergency care now and provide a blueprint for a network of care in the future.

“He is not proposing any downgrading but believes after this process the overall number of emergency care centres will remain broadly the same.”

Senior doctors say that the present system is on the brink of collapse, adding that last winter many casualty units became like “warzones” as they struggled to cope with demand. The NHS proposals, published on Wednesday, include same-day access to family doctors for routine health problems seven days a week, and GP telephone appointments.

The report also calls for extended training for paramedics to keep more patients out of hospital, with evidence suggesting that up to half of 999 calls could be managed at the scene.

Under the plans, the controversial 111 phoneline would have a central role in managing demand for urgent care. Senior NHS officials said that despite problems which have dogged the non-emergency telephone line, which collapsed in some parts of the country when it was introduced earlier this year, an “enhanced” version of the service would help improve care.

In future, call centres will have more medical staff on hand, and staff will be able to access electronic patient records so that advice was better tailored, they said.

Sir Bruce said that a transformation of the whole system of urgent care was “the only way to create a sustainable solution — and ensure future generations can have peace of mind that, when the unexpected happens, the NHS will still provide a rapid, high quality and responsive service free at the point of need”.

He said the NHS needed to acknowledge that A&Es are all not of equal quality — with one in seven operating without intensive care departments and one in five without a paediatric department.

Officials said the current system of A&E departments had not been reviewed since the Seventies, when heart attacks were treated with bed rest, with one in four dying. Today, advances in cardiology have reduced death rates to five per cent.

Sir Bruce insisted the changes would not mean closures of A&E departments, with “no degradation” of the service currently provided at casualty units.

Under the plans, standard emergency departments that receive cases requiring specialised care would be expected to be able to stabilise patients, before transferring them

Officials also said a plethora of extra services set up to relieve pressure on casualty units, such as walk-in centres, urgent care centres, and minor injury units, had created a “whole heap of confusion” for patients about where to turn, and should be rebranded with one name to provide consistent services.

The principles behind the changes were broadly welcomed last night by medical experts, charities, patients groups and think tanks.

However, changes to scores of hospitals across the country, in which specialist services such as acute stroke units would be centralised, are likely to prove more controversial as decisions are taken about which hospitals will see services stripped back, and when details emerge of the distances between major centres, especially in rural areas. Changes to centralise stroke care in London were made in 2010 and have been credited with saving 400 lives. However, the former head of NHS London said last year that hundreds of patients died or suffered disability in the years before, amid political arguments which delayed the changes.

Concerns were raised last night about the role of 111 in the strategy, with patients groups saying it would need to improve on a “woefully inadequate” performance before it could cope with an expanded role.

Officials at NHS England said further plans would be published within months, setting out the costs of the changes and the implications for the NHS workforce.

The proposals could become a political battleground in the run-up to the next election. On Tuesday, Mr Hunt told the House of Commons he would not “stand in the way of changes” that save lives.

Andy Burnham, the shadow health secretary, welcomed Sir Bruce’s recommendations but accused ministers of an attempt to “abdicate all responsibility for the crisis in A&E”.