Leading figures from the health world are calling for a national debate on how the NHS in England is funded.
In a letter to The Times, they say challenges from an ageing population mean the system is "creaking at the seams" and cannot continue as it is.
Signatories include the heads of the Royal College of Physicians and Royal College of Nursing.
The BBC's health editor says the group feels future options may include higher taxes or charges for some treatment.
Without action an extra £30bn will be needed by 2020 to fund the NHS at current levels, their letter adds.
They are asking for a cross-party, independent conversation on the way forward for the "scope, provision and funding of health and social care".
The nine signatories say that in 50 years' time, at least two-and-a-half times as many patients will suffer from multiple health problems.
BBC health editor Hugh Pym said while their letter is suggesting that further action is needed to make the NHS more efficient, this will not be enough as financial pressures intensify.
"The group is calling for a national debate on what it says are the options - higher taxes, payments for some elements of health care or a review is what is available on the NHS," he added.
Their letter says: "The status quo is not an option. We are already seeing the signs of the system creaking at the seams."
Warning that "business as usual won't do", they assert there needs to be "an honest, open dialogue between politicians and citizens".
"We need a new settlement; a fundamental, holistic agreement with the country on what health and social care should be, how and where it is delivered to maximise the quality of care, and how it should be paid for."
This "national conversation" should start now and be completed by the end of 2015, the letter concludes.
Two signatories - Ciaran Devane, chief executive of Macmillan Cancer Support, and Turning Point chief executive Lord Adebowale - are non-executive directors of NHS England.
It is also signed by: Sir John Oldham, who chaired the Independent Commission on Whole Person Care; Jeremy Hughes, chief executive of the Alzheimer's Society; Peter Carter, chief executive of the Royal College of Nursing; Maureen Baker, chairwoman of the Royal College of GPs; Sir Richard Thompson, president of the Royal College of Physicians; Jean-Pierre van Besouw, president of the Royal College of Anaesthetists, and Chris Hopson, chief executive of the Foundation Trust Network.