Three senior NHS staff in London claim they have been suspended for whistle-blowing after raising concerns about the hospitals they work in, but have been given other reasons for keeping them off work.
As NHS staff they are entitled to protection under the Public Disclosure Act 1998 from dismissal or victimisation if they have concerns about misconduct and malpractice.
But the three health trusts concerned have denied suspending them for speaking out.
The trio became whistle-blowers because of fears about standards of care, they told BBC London's Inside Out programme.
Ramon Niekrash, a surgeon at Queen Elizabeth Hospital in Woolwich, south London, said he complained to his manager because he did not believe local health services were "adequate" or "safe".
"The concerns related to staffing levels" and the number of clinical nurse specialists for cancer, he said.
He also said a patient who had a biopsy on his prostate which was positive for cancer had to wait six months to be seen by a consultant.
"I was escorted to the chief executive's room," he said
"They basically said that a number of concerns had been raised [about me] and that I was to be suspended."
Mr Niekrash subsequently won a legal battle to be reinstated but had to pay a £140,000 legal bill.
The South London NHS Trust said: "We believe that the process of events which happened to Mr Neikrash would not happen now.
"We are working with clinicians… to get better reporting and processes in place so that genuine concerns about patient safety are heard, considered properly and appropriate action taken to correct problems."
'Stunned and humiliated'
Radiologist Sharmila Chowdhury was the imaging services manager in charge of 60 staff when she was "marched off the premises" at Ealing Hospital in west London.
She claimed to have discovered what she believed were "anomalies" in her department's budget.
"My main role was to manage the budget, day in, day out. I was concerned because I wasn't sure I hadn't got it wrong.
"When I found anomalies I did raise the issues with the line manager and senior managers."
She said she was "stunned and humiliated" by her treatment.
Ealing Hospital NHS Trust said there was "an ongoing internal process" regarding her case and it would not comment further "at this stage".
'Clear my desk'
Henry Fernandez, a nurse with the Kent and Medway NHS Trust, received a £70,000 settlement before a tribunal was due to take place, after he made complaints about his department.
He said he was told "to go back to my office, clear my desk and get off the premises".
In Mr Fernandez's case the Trust did not accept he was penalised for whistle-blowing and said that "an out-of-court settlement was discussed with Henry Fernandez for unfair dismissal but no agreement was reached".
"We do not consider the Public Disclosure Act to apply in this case as Henry Fernandez was not an NHS whistle-blower," it added.
Inside Out has spoken to other NHS staff who said they had been suspended for highlighting concerns at work.
They said they were still being paid by their employers but had not been allowed to return to work.
A Freedom of Information (FoI) request by the programme discovered nearly 600 NHS staff in London were suspended in 2009/10.
A total of 56 of London's 71 hospitals responded to the FoI request asking how many staff were suspended last year.
There were 514 staff, plus 84 doctors and dentists who are being were paid to stay away from work.
The cost of their wages reached a figure of £3m.
However these figures cover suspensions for reasons which include illness, "gardening leave" between jobs and those who have been suspended but claim the action taken against them was for whistle-blowing.
You can see more on this story on Inside Out on BBC One in London at 1930 BST on Monday 25 October.