Doctors have warned that plans for "brutal " NHS cuts are shrouded in secrecy and will cause uproar once revealed.
The British Medical Association (BMA) says health service leaders have refused to publish details of the proposals that could extend waiting times, reduce access to services, cut down on prescriptions and treatments, and even merge or close hospitals and facilities.
The proposals are being discussed under the capped expenditure process - which was introduced this year to cap NHS spending in some areas in order to meet so-called "control total" budgets in 2017/18.
The BMA submitted Freedom of Information requests to NHS Improvement and each of the 13 areas, asking for the proposal documents.
Eight of the 13 areas responded - but, according to the BMA, none of them provided the full document or any significant details.
BMA council deputy chairman Dr David Wrigley said: "These plans could have serious consequences for doctors working on the frontline and for the care and treatment patients receive and can expect in hospitals and GP surgeries in these areas.
"It is bad enough that brutal cuts could threaten the services, but it is totally unacceptable that proposals of this scale, which would affect large numbers of patients, are shrouded in such secrecy."
He added the Government should stop and think before pressing ahead with the process.
Speaking anonymously to the BMA, one trust chairman with oversight of the process of drawing up the plans in his area, said: "We were descended on and asked to think the unthinkable in no time at all. The NHS seems to go into a zone of secrecy as an automatic reaction.
"That's the thing that really upsets me - the secrecy of it all and the ridiculous pace in which solutions are to be crafted and agreed. It's the management culture too - it's all hierarchical power and bullying. Even the most modest proposals would cause uproar."
An NHS spokesman said: "While this report is just recycling old claims from several months ago, the NHS has always had to live within the budget that parliament allocates, and the usual requirements for public consultation on any suggested major service reconfigurations of course continue to apply.
"However, it is grossly unfair if a small number of areas in effect take more than their fair share at the expense of other people's hospital services, GP care and mental health clinics elsewhere in the country."