The NHS will not survive unless there are radical changes in the delivery of health care such as hospital closures and centralisation of services, experts said.

If there is not ''fundamental change'' to the health service, there could be more and more instances of the appalling care suffered by patients at Stafford Hospital, health officials warned.

An ageing population, more and more people suffering from long-term conditions and a stagnant budget are compounding factors putting pressure of the system, NHS England said.

And if health service in England was to continuing to delivering care the way it currently is, there will be a funding gap of £30 billion between 2013 and 2021, even if the health budget is protected, officials said.

So to maintain a health service that is ''free at the point of use'' a new approach to the delivery of services is ''urgently needed'', they said.

A new NHS England document says that improving the current system ''will not be enough'', adding: ''Without bold and transformative change to how services are delivered, a high quality yet free at the point of use health service will not be available to future generations.''

Officials have not yet decided how the health service must change and have decided to open up national debate to ''flesh out the no-go areas''.

But plans to make changes to health services have been ferociously opposed in the past.

For instance, the streamlining of children's heart surgery services ended up in a bitter legal dispute. And campaign groups in Stafford are battling to maintain services at Mid Staffordshire NHS Foundation Trust - even though Stafford Hospital was at the centre of a care scandal that rocked the system to its core.

NHS England said that moves such as the centralisation of services - where care is concentrated in a few specialist centres to ensure quality of care - would form part of the transformation.

Medical director Professor Sir Bruce Keogh said that a number of services had the potential to be concentrated at fewer specialist centres, such as treatment for heart attacks and strokes, operations on veins and arteries and bowel surgery.

He said that some services would only need be centralised for a limited time, giving the example of pacemakers - in the past the devices, which regulate a patient's heartbeat, could only be implanted by specialist doctors in a small number of centres, but now the procedures are conducted regularly in any hospital which employs a cardiologist.

Officials also said that patients will also have to take ''greater control of their health'' - particularly those with long term conditions such as diabetes, depression, dementia and high blood pressure.

The new design must provide better services for preventing disease, they said. At present only 4% of the budget is spent on prevention but officials want to examine whether this can be ''scaled-up over time''.

They also said health systems would have to harness emerging technologies more ''efficiently and effectively'' and hospitals will also have to look at delivering care differently.

For instance, at Guy's and St Thomas' NHS Foundation Trust in London experts have developed a ''e-intensive care unit'' where specialists remotely monitor patients using high definition cameras, two-way audio systems and other instruments that keep track of patients' vital signs.

In a new document, titled ''A Call to Action'', officials said: ''The NHS is one of our most precious institutions. We need to cherish it, but we also need to transform it.

''Future trends threaten its sustainability and that means making some tough decisions now to ensure its future is guaranteed.

''Even protecting the budget will not address the financial challenges ahead.

''If the NHS is to survive another 65 years it must change.

''Preserving the values that underpin a universal health service, free at the point of use, will mean fundamental changes to how we deliver and use health and care services''.

Outgoing NHS England boss Sir David Nicholson said that after the public debate on the challenges, local health authorities will develop plans on how the health landscape will change in each region.

''We need to create £30 billion worth of resource in the NHS by cutting off the increase in demand through things like prevention, we need to do it by changing services so that they are delivered in different environment and we need to drive efficiency in the system,'' he said.

''The reason it is so important that we have this conversation now is at the end of this year, we are going to have to make some really big, serious decisions about the way in which we invest and allocate resources in 2014/15 and 2015/16.

''We don't believe (those decisions) can be made in isolation at the centre, nor without proper discussions with the public and patients on how we make that happen.''

He said the health service cannot ''muddle and sleep walk'' through the challenges it faces or there could be more instances of care failing such as those witnessed in the Stafford Hospital scandal.

He added that the current regulatory system around making changes is ''very slow'' and said that he will be asking the Government to assess how the process can be sped up.

Sir Bruce added: ''The NHS is caught in a triple pincer of increasing demand, rapidly escalating cost and constrained resources and all of that is against a background of increasing expectations of quality of care and they are expecting the principles of the NHS to be pertained - which is essentially free at the point of delivery.

''We need to understand what people will accept and what they won't.''

Officials said that they are open to hearing ideas on how to address the funding gap but they have pledged that they will not ''cut or charge for fundamental services or privatise the NHS''.