Treatment on the NHS is unlikely to be free at the point of use in 10 years' time, a leading think tank has warned.
The Nuffield Trust depicted the grave situation facing cash-strapped NHS trusts in its Into the Red report.
Tax hikes or charges would be inevitable without sustainable funding to plug a £28-34 billion hole in the health service's finances by 2021-22, the report stated.
"Without sustained and unprecedented increases in health service productivity, funding for the NHS in England will need to increase in real terms between 2015 and 2022 to avoid reductions in the level or quality of services. However, this funding increase is looking increasingly unlikely," the report's co-author, Adam Roberts, said.
In the trust's first poll of 100 leading healthcare experts, two-thirds believed trusts would have to go into deficit to provide a high-quality service while half were not convinced the NHS would be able to provide a free at the point of use service in a decade.
Out of 249 trusts, sixty-six finished the year in the red, according to provisional figures for 2013-14, which amounted to an overall deficit of about £100 million, compared with a £383 million surplus the previous year.
Doubts over the end of a 'free NHS' has been echoed by one of Scotland's leading breast surgeons, Dr Philippa Whitford, who has broken ranks about her NHS fears to gain support for the Yes Scotland campaign.
The 55-year-old said: "In five years, England will not have an NHS and in 10 years, if we vote no, neither will we.
"If we do not vote yes in September, I will be heartbroken. I have spent 32 years working in the NHS and it is very dear to me."