Health service managers have called on the government to be more honest about the financial challenges facing the NHS in England.The NHS Confederation says a lack of candour over funding is damaging as the public may resist a service being cut.
This, say managers, can lead to potentially dangerous "salami slice" cuts across the board.
But the coalition government says health spending is growing and the NHS is becoming more efficient.
Compared with other departments, health did well in the coalition's spending review.
The government promised to increase funding in England in real terms, year on year, throughout this parliament.
But a lot of chief executives are pessimistic. They feel they are grappling with a spending squeeze, facing unpopular decisions involving cuts and closures without political cover.
Mike Farrar, chief executive of the NHS Confederation, says there is no public understanding of why changes are needed.
"It's very difficult for NHS managers and clinicians to make those necessary changes, and the alternative to getting public support for that is that they make unplanned cuts which are frankly in some cases rather dangerous to care that people need."
'Parallel universe' A lot of this pressure comes from a plan called QIPP - Quality, Innovation, Productivity and Prevention.
This scheme, first announced under Labour, aims to save £20bn over four years through improved efficiency, with the money going back into front-line services.
But some trust chief executives - speaking anonymously - have told the BBC that the true agenda is about cuts.
One trust chief executive said ministers were not being straight with the public: "What people cannot tolerate is the lack of honesty about some of the tough choices that we're having to make.
Another said: "Many chief executives - just about all that I speak to, believe that we're living in a parallel universe."
The bulk of the NHS budget still goes through primary care trusts.
Anita Charlesworth, former director of public spending at the Treasury who is now with the health research group the Nuffield Trust, says their real-terms funding increase has become a real-terms cut.
"The government has increased the money available to local health authorities to buy care by 3%.
"But when you take into account inflation and the fact of those health authorities being asked to hold back some money to prepare for contingencies and pay for one-off investments, the money that they've got available to spend with hospitals is 3% lower in real terms on average."
On top of this comes productivity savings - averaging 4-5% a year.
'No reinvestment' The outlook for hospitals is even tougher.
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End Quote NHS community and mental health trust chief executiveI worry most about the most vulnerable”
In some places the strain is starting to show, with restrictions on access to services and a rise in the number of patients waiting more than 18 weeks for hospital treatment.The chief executive of the Royal College of Nursing, Peter Carter - who ran a mental health trust for 12 years - says he hears this from managers all the time.
"They feel that they're being duplicitous for having to sell it to their staff, the public, their stakeholders by saying all of this money is coming back in. It is not coming back in. There is no evidence of any re-investment."
In a statement the Department of Health insisted that the service was becoming more efficient.
"Despite protecting the NHS budget, we know that the NHS will have to do more clinical work in the face of a flatter settlement - but that settlement is one of the best in Whitehall and we will keep our promise on increasing it in real terms."