Whistleblowers in the public sector have been "shockingly treated" despite the vital role they play in exposing wrongdoing, according to parliament.
The House of Commons Public Affairs Committee (PAC) said in a report that it had heard evidence of whistleblowers being "victimised" by colleagues and managers, a situation that deters others from coming forward.
MPs on the PAC recommended that when the identity of a whistleblower is known then the public body must ensure the individual is protected, supported and has their welfare monitored.
And departments should "provide all employees with a route map that clarifies suitable internal and external reporting routes" so staff know to whom they can blow the whistle.
"Far too often whistleblowers have been shockingly treated, and departments have sometimes failed to protect some whistleblowers from being victimised," said Margaret Hodge MP, who chairs the PAC.
"We have heard of too many cases of appalling treatment of whistleblowers by their colleagues, but departments were unable to tell us if those who have threatened or victimised whistleblowers had been sanctioned.
"This lack of action has a profound impact on confidence and trust in the system, and means that employees are less likely to blow the whistle for fear of what may happen to them."
In one high profile example, nurse Margaret Haywood was struck off by the Nursing and Midwifery Council after she filmed the abuse of elderly people at the Royal Sussex Hospital for a Panorama documentary.
UK law protects whistleblowers if they act in good faith and alert the right people to malpractice, which includes the media in some circumstances.