The outgoing head of the NHS has said hospitals will have to close and services centralised to improve patient care.
Sir David Nicholson called for a radical reorganisation of health services so a smaller number of larger hospitals offer most major surgery while smaller hospitals scale back the care they provide.
In an article in the Daily Telegraph, he warned that the NHS could face a £30 billion funding shortfall in just seven years unless it changes the way it provides services.
He called on politicians from all parties to back the controversial reforms, which he fears otherwise could be used to score party political points in the run up to the next general election.
Sir David, head of NHS England, told the paper: "I believe the NHS needs to embark on a programme of transformational change to front-line care, arguably the most significant since its creation."
He said the service was "fragmented and confusing" for patients and did not always provide the best possible care for the sick.
And he warned that the NHS simply could not afford to delay the proposed changes
He said: "Like every major health system in the world, we face a big financial problem for the future: the sums don't add up.
"If we don't change, we face a funding gap that could be £30 billion by 2021.
"We know that centralised, large units, with concentrated expertise and technology, work best in providing the most effective care.
"So we need to ensure this approach is applied to other parts of the health service, for people with very rare conditions, and for significant planned surgery."
Without sweeping change, services will not be sustainable, he said, adding : "Our NHS does a superb job for millions of people, day in day out, but it cannot stand still - it needs to adapt to survive."
Last year NHS England published proposals calling for the centralisation of major hospital services.
And over the next few months it is due to set out its plans for changes for specialist services, and proposals to ensure GPs provide more services serving larger populations.
The proposals have sparked controversy with fears that many towns will be stripped of their emergency facilities.
But Sir David insisted the changes are crucial to improve the welfare of patients.
He wrote: "The NHS proposals for change always come with controversy.
"Too often the overall public interest gets lost in a debate about winners and losers with too much focus on buildings and not enough on services.
"This time I hope the NHS, the public, policy makers and politicians will join forces to make it happen. As someone who has spent 30 years working in the NHS, I know it matters too much to get it wrong."
He also called for the NHS to do more to "listen to patients and act on their concerns" and make full use of technology to ensure the public is "fully empowered and included in all aspects of the NHS".
Sir David will retire next month after a year in which he has been heavily criticised over his part in the Mid Staffordshire Hospital Trust scandal.
He was in charge of the health authority supervising Stafford Hospital for two years before being appointed NHS chief executive in 2007.