Failings in care and problems with staffing at the 14 hospital trusts with the worst death rates in England are to be exposed.
Eleven hospitals are being placed in special measures because of major failings, the government has announced.
The investigation was launched earlier this year following the public inquiry into the Stafford Hospital scandal.
Health Secretary Jeremy Hunt said the trusts, among 14 investigated for high death rates, had problems so entrenched that tough action was needed.
The probe has been led by NHS England's medical director Prof Sir Bruce Keogh.
He cited examples of staffing problems, poor care and weak leadership as he announced the move in Parliament.
It has focused on whether the figures indicate sustained failings in the quality of care and treatment at the trusts.
The other three trusts investigated were also told to make improvements following the review.
Investigators have been looking at whether existing action by the trusts to improve quality is adequate or whether they are in need of any "additional external support".
But the health secretary said investigators had confidence the leadership at those trusts was capable of making the changes needed.
The report was ordered amid concern that failing hospitals were not being held to account following the criticisms of the Francis Inquiry into Stafford Hospital, which said the public had been betrayed by a system which put "corporate self-interest" ahead of patients.
As part of the process of special measures for the other 11, teams of external experts will be sent into the organisations to work with the senior management team.
Its understood the Keogh report - as well as flagging up management failings - will also point to concerns over nurse staffing levels in the 14 hospitals under investigation.
Regular updates on their progress will also be given.
The report will suggest there is a link between inadequate staffing levels and poor standards of care.
Mr Hunt set out a detailed breakdown of the problems identified at the individual trusts, but among the common themes identified were:
Its expected the report will say: "When the review teams visited the hospitals, they found frequent examples of inadequate numbers of nursing staff in some ward areas."
• Patients being left on trolleys, unmonitored for excessive periods and then being talked down to by consultants
Sir Bruce Keogh's report will say all 14 hospitals are undertaking an urgent review of "safe staffing levels."
• Poor maintenance in operating theatres, potentially putting patients in danger
On staff morale it says - "It was clear that staff did not feel as engaged as they wanted or needed to be: yet academic research shows that the disposition of staff has a direct influence on mortality rates."
• Patients often being moved repeatedly between wards without being told why
Prof Sir Brian Jarman, an expert on mortality rates who contributed to the report, told the BBC that his data showed that over a period of seven years there were about 13,300 more deaths than would have been expected.
• Staff working for 12 days in a row without a break
He agreed it was closely linked to staffing levels.
• Blood being taken from patients in full view of the rest of the ward
"Doctors make mistakes if they are overworked," he said. "If you don't have enough trained nurses, as with doctors, you get higher death rates."
• Low levels of clinical cover - especially out of hours
The trusts investigated, which run a total of 19 acute hospitals, are the ones with the highest death rates in 2010-11 and 2011-12. They are:
Mr Hunt said: "We have taken swift and tough action to make sure these hospitals are given all necessary support to improve.
• Basildon and Thurrock University Hospitals NHS Foundation Trust
"We owe it to the three million people who use the NHS every week to tackle and confront mediocrity and inadequate leadership head on."
• Blackpool Teaching Hospitals NHS Foundation Trust
The investigation into the 14 trusts was launched earlier this year following the public inquiry into the Stafford Hospital scandal, which said the public had been betrayed by a system which put "corporate self-interest" ahead of patients.
• Burton Hospitals NHS Foundation Trust
The trusts were identified as they had the highest death rates in 2010-11 and 2011-12.
• Colchester Hospital University NHS Foundation Trust
The probe has been led by NHS England's medical director Prof Sir Bruce Keogh and focused on whether the figures indicated sustained failings in the quality of care and treatment at the trusts.
• The Dudley Group NHS Foundation Trust
Sir Bruce said: "Not one of these trusts has been given a clean bill of health by my review teams.
• East Lancashire Hospitals NHS Trust (Two hospitals - Burnley General and Royal Blackburn)
"These reviews have been highly rigorous and uncovered previously undisclosed problems.
• George Eliot Hospital NHS Trust
"I felt it was crucial to provide a clear diagnosis, to write the prescription, and, most importantly, to identify what help these organisations might need to support their recovery or accelerate improvement.
• Medway NHS Foundation Trust
"Mediocrity is simply not good enough and, based on the findings from this review I have set out an achievable ambition which will help these hospitals improve dramatically over the next two years."
• North Cumbria University Hospitals NHS Trust (Two hospitals - Cumberland Infirmary and West Cumberland)
The 11 trusts in special measures are: North Cumbria University Hospitals NHS Trust, Northern Lincolnshire and Goole Hospitals NHS Foundation Trust, Tameside Hospital NHS Foundation Trust, United Lincolnshire Hospitals NHS Trust, Basildon and Thurrock University Hospitals NHS Foundation Trust, Burton Hospitals NHS Foundation Trust, East Lancashire Hospitals NHS Trust, George Eliot Hospital NHS Trust, Sherwood Forest Hospitals NHS Foundation Trust, Buckinghamshire Healthcare NHS Trust, Medway NHS Foundation Trust.
• Northern Lincolnshire and Goole Hospitals NHS Foundation Trust (Three hospitals - Diana, Princess of Wales Hospital, Goole and District Hospital and Scunthorpe General)
The other three investigated are: Blackpool Teaching Hospitals NHS Foundation Trust, The Dudley Group NHS Foundation Trust and Colchester Hospital University NHS Foundation Trust.
• Sherwood Forest Hospitals NHS Foundation Trust
Between them the trusts run 19 acute hospitals.
• Tameside Hospital NHS Foundation Trust
• United Lincolnshire Hospitals NHS Trust
At the moment, regulatory action is being taken against six of the trusts, but none is facing the ultimate sanctions of fines, closure of individual units or administration of the entire organisation.
Key questions
Action Against Medical Accidents chief executive Peter Walsh said: "These investigations are welcome but well overdue. The problems at these trusts were known to the authorities well before any decision to look into them.
"What patients most want to know are answers to some key questions. Are these hospitals safe now? Is the regulatory system now robust enough to detect problems when they arise and intervene quickly to protect patients? Will those responsible for allowing these avoidable deaths to go on be held to account?"
Roger Taylor, of Dr Foster, a research company that has pioneered the use of mortality data, said: "In the past, there has been a culture in the NHS, which at best aims to reassure the public and at worst seeks to conceal failings.
"That culture has had its day. The reluctance to speak plainly about the risks to patients has meant that, too often, poor care has been allowed to continue. The desire to support organisations struggling to provide a high standard of care in difficult circumstances has cost patients their lives."
The Stafford Hospital inquiry was launched after data showed there had been between 400 and 1,200 more deaths than would have been expected.
It is impossible to say all of these patients would have survived if they had received better treatment, but evidence made it clear many were let down by a culture that put cost-cutting and target-chasing ahead of the quality of care.
Examples included patients being so thirsty that they had to drink water from vases and receptionists left to decide which patients to treat in A&E.
