An NHS whistleblower told Daybreak if he had his time again he would not raise concerns about patient safety for fear of retribution.
Spekaing to ITV News, NHS England's new boss Simon Stevens has admitted that standards have not been good enough within the organisation.
The new NHS boss may want to make cuts to tackle a £30 billion shortfall, but could face a fight with a General Election approaching.
A woman who developed severe dehydration after suffering a urine infection in hospital says doctors and nurses failed to spot clear signs she was unwell.
Maura Murray said that despite showing "classic symptoms" of dehydration, "nobody seemed terribly concerned" at her condition, which eventually led to life-threatening loss of kidney function.
One of the authors of a report into deaths from Acute Kidney Injury has said hospital staff must be "more vigilant" about ensuring patients are properly hydrated.
Dr Donal O'Donoghue's research suggests as many as 1,000 patients a week are dying in the NHS from avoidable kidney problems.
The co-author of a study that found 1,000 hospital patients were dying from 'avoidable' kidney problems has described the findings as "unacceptable".
"Good basic care would save these lives and save millions of pounds for the NHS," said Professor Donal O'Donoghue, consultant renal physician at Salford Royal NHS Foundation Trust.
Doctors and nurses need to make "elementary checks" to prevent [acute kidney injury], Dr O'Donoghue said.
"They also need to be aware that some common medications increase the risk of AKI."
A spokesman for NHS England said: "We have taken steps to ensure the NHS puts in place coherent long-term plans to reduce avoidable deaths in our hospitals, and to improve the way data is used in decision making."
At least 1,000 hospital patients in England die each month from avoidable kidney problems, according to a new study commissioned by the NHS.
Researchers found that acute kidney injury (AKI) causes between 15,000 and 40,000 excess deaths every year.
The condition refers to a loss of kidney function and can develop very quickly. It can occur in people who are already ill with conditions such as heart failure or diabetes, and those admitted to hospital with infections.
AKI can also develop after major surgery, such as some kinds of heart surgery, because the kidneys can be deprived of normal blood flow during the procedure.
AKI costs the health service over £1 billion every year and is responsible for nearly eight times as many deaths as superbug MRSA at its peak, according to a study commissioned by NHS Improving Quality.
Radical plans to increase national insurance contributions to fix a looming £30 billion a year "black hole" in NHS funding and pay for elderly care are being examined by Labour's policy review.
According to the Observer, senior party figures said that a scheme advanced by the former Labour minister Frank Field – under which funds from increased NI would be paid into a sealed-off fund for health and care costs – is being examined, though no decisions have been taken.
Mr Field said: "In no way can we have anything like the NHS we have now if we are running such a huge deficit every year. We have to think about the second phase of the life of the NHS. It has to be reborn. Otherwise it will be unsustainable in a few years' time."
The heart doctor turned whistleblower who won his unfair dismissal case said he felt he needed to speak out because the trust repeatedly ignored his complaints about the treatment of patients.
Dr Raj Mattu told BBC Radio 4's Today programme:
– Dr Raj Mattu
I was rather concerned that the reason I came into medicine, which was to care for patients and to hopefully save lives, was not a priority or certainly a primary aspect of what managers in the hospital in Coventry were focused on.
Patient safety was regularly put at risk and patients were dying that I felt would not have died at other hospitals I had worked at.
A heart doctor turned whistleblower who exposed NHS safety fears said he felt "vindicated" after winning an unfair dismissal case following a long dispute with hospital bosses.
Cardiologist Raj Mattu claimed there was not enough protection available for whistleblowers in the NHS and added that he wants a meeting with Health Secretary Jeremy Hunt to address his concerns.
Dr Mattu exposed fears for patient safety and overcrowding at Walsgrave Hospital in Coventry in 2001, claiming there may have been avoidable deaths as a result.
He was then "vilified and bullied" by the University Hospital of Coventry and Warwickshire NHS Trust during a years-long "witch hunt", according to his lawyers Ashfords LLP.
While steps have been taken to reduce infection rates of hospital bugs such as MRSA and Clostridium difficile, other infection rates are still too high, the Nice said.
A spokeswoman said doctors and nurses must "redouble" hygiene efforts to bring the rates down.
– Professor Gillian Leng
It is unacceptable that infection rates are still so high within the NHS. Infections are a costly and avoidable burden. They hinder a patient's recovery, can make underlying conditions worse, and reduce quality of life.
Although there have been major improvements within the NHS in infection control, particularly in relation to Clostridium difficile and MRSA bloodstream infections in the last few years, healthcare associated infections are still a very real threat to patients, their families and carers and staff.
One in 16 people receiving NHS care are picking up infections, health officials have warned.
The National Institute for Health Care Excellence (Nice) says he level of infections are "unacceptably high" and are a "very real threat" to patients.
Every year around 300,000 people get an infection while being cared for by the health service in England.The most common type of infections include pneumonia, lower respiratory tract infections, urinary tract infections and surgical site infections.
These infections can occur in otherwise healthy people, especially if invasive procedures or devices like catheters or vascular access devices, are used, Nice said.