Health and social care could consume half of government spending in 50 years' time, a think tank has predicted.
By 2060, 50% of UK public spending could be allocated to treating and caring for people - a stark rise from the 9% currently spent. Analysts at The King's Fund based their projections on economic growth and current levels of taxation and government expenditure.
The new report states that population changes, increases in wealth and medical advances will increase pressure to spend more on health and social care in the future.
Researchers state that the ageing population will also be a factor, but will only be attributable to a small rise. The authors said that increases on this scale were not inevitable.
They said that difficult choices lay ahead - including the possibility of increased taxation or limiting the scope of publicly funded services. There should be an "informed public debate" about the choices and ministers should commission regular reviews of spending pressures, the authors said.
John Appleby, chief economist at The King's Fund and author of the report, said: "While there is nothing inevitable about spending on health and social care continuing to increase in line with historic trends, the pressure to spend more is likely to see it consuming an ever-larger proportion of national income.
"It is time to think much more long-term about how much we should spend, the benefits of this spending and how it should be paid for. By turning the spotlight on these issues now, we hope to stimulate an informed debate about the difficult choices ahead."
NHS Confederation chief executive Mike Farrar said the report "highlights the financial pressures coming down the tracks". He said: "There is a growing consensus that the NHS must change to meet the needs of our changing population, make the most of healthcare technology, and live within its means.
"Addressing these issues will require some tough choices and it is essential that we have open and honest conversations with the public about what we can afford in the future and how we will fund it.
"We urgently need an all-party debate about how we can establish a sustainable health and social care system, with radical solutions very much allowed."