Sir Robert Francis QC said bullying was “undoubtedly a problem” and a change of culture within the health service was necessary to protect staff who raise concerns about poor patient care.
The findings of Sir Robert’s Freedom to Speak Up review, which was ordered by Health Secretary Jeremy Hunt, are due to be published later.
Sir Robert told the BBC that a survey carried out as part of the review found “some 30% of people who had raised a concern said they felt unsafe after they had done so”, while others said they did not trust the system or were reluctant to speak out because they “feared being victimised”.
He said: “All that climate of fear is brought about by the experiences of maybe a very few people.”
Sir Robert told Radio 4’s Today programme: “I have spoken to people who have not only lost their jobs, they have lost their livelihood, they have not been able to find other jobs to do and I’m afraid in some cases have felt suicidal and become ill as a result.
“So the stresses and strains of wanting to do the right thing can be immense.”
Sir Robert said the culture needed to change so that raising and dealing with concerns became a normal occurrence across the NHS.
He said: “Day in, day out, thousands of members of NHS staff raise concerns, talk about problems with their colleagues and they get them sorted out.
“That’s the way it should be and in well-run organisations, well-run departments, that’s just the accepted way of life.
“But there will always be concerns that people raise which inevitably affect the reputations or the assessments of other people, and reactions to that can be defensive - that’s human nature.
“What we need are systems which make those sorts of conversations normal rather than something that is aggressive and threatening.”
Sir Robert added: “Bullying is something I heard a lot about in the course of my review and it is undoubtedly a problem.
“Of course, what one person perceives as being bullying may be another person’s firm management but what I would say is that conduct which amounts to bullying or is perceived as bullying is, in itself, a safety issue.”
Asked whether he thought a new law might be necessary to address the issue, Sir Robert said he did not think legislation was the answer.
“What I have been looking at largely is how do we set about changing a culture? You need to make it absolutely normal for people who are professionals who see something they are worried about to raise that with someone who can do something about the concern.
“A lot of what happens where things go wrong is, when someone raises a concern, it descends into a debate about personalities rather than anyone establishing what the facts are.”
In another interview, Sir Robert told the BBC a “significant proportion” of health workers were afraid to speak out.
He said: “Time and time again, people say to me they either want to complain about the behaviour of others towards them or, when they do raise a concern about the working environment or the way patients are being treated, the reaction to them has been one of being bullied.
“I’ve heard some frankly shocking stories about (staff) whose health has suffered, and in rare cases who’ve felt suicidal as a result of their perception of them being ignored, or worse.”
One doctor who exposed safety concerns at a hospital said whistleblowers in the NHS were being persecuted “on a grand scale”.
Cardiologist Raj Mattu publicly exposed overcrowding and fears for patient safety at Walsgrave Hospital in Coventry in 2001, claiming there might have been avoidable deaths as a result.
He told BBC Breakfast he “couldn’t possibly recommend” other NHS staff voicing safety concerns because of the lack of “sufficient protections”.
Dr Mattu said: “It’s frustrating and depressing to hear that whilst there is often and periodically noises made about ... protecting whistleblowers, the reality is there are very few palpable, material changes that take place.
“Today even, the culture is very unsafe. There is still ongoing persecution of whistleblowers on a grand scale.
“Large numbers of managers in the NHS are in there for a different reason to the nurses and doctors. Most of us come in because we want to care for people. Managers largely come from a background of wanting a career in management.
“Many of us who are whistleblowers feel compelled and a moral obligation to speak up.
“I saw practices in my hospital that were putting patient safety and lives at risk.”
Dr Mattu said any further recommendations after Sir Robert’s review were “of no value if they are not going to be enforced”, and called for independent scrutiny of whistleblowing concerns in the NHS.
He added: “At this moment in time, as of today, I don’t believe there are sufficient protections in place that are of any value. I couldn’t possibly recommend anybody else whistleblow at this moment and go through the sort of ordeal I and others have gone through.”
The Health Secretary said: “Since Mid Staffs, there have been significant changes to make the NHS more open, safe and transparent. But more needs to be done and this is why we asked Sir Robert to carry out this important piece of work.
“We agree with Sir Robert that listening to patients and staff is absolutely vital and will be responding to this report later today.”