Faltering steps towards openness in the public service have been taken over the years, yet there is still so much farther to go. The Freedom of Information Act tilted the presumption in favour of disclosure – to such an extent that MPs were caught unawares by their own law over their expenses claims. And the Public Interest Disclosure Act of 1998, the so-called whistleblowers' charter, is supposed to protect public servants that report mistakes, maladministration and corruption. But in practice, the Act is a long way from an effective mechanism for encouraging honest and open feedback from people working at the front line.

As we report today, whistleblowers in the National Health Service continue to be treated in the way that the bringers of bad news always have been in authoritarian cultures. They are – metaphorically these days – taken out and shot, when they should be learned from and congratulated. For decades, the NHS has been plagued, as might be expected of any large bureaucracy, by dark corners of poor management. Worse than that, it has tended to respond to whistleblowers who draw attention to poor practice by suspending or transferring them, trying to belittle or discredit them, and covering up the problem.

This is not, of course, because managers want patients to be harmed unnecessarily, but because they want to fix the problem on the quiet, in order to avoid damage to the reputation of their institutions. That is not good enough, because, in the American saying that is particularly apt, sunlight is the best disinfectant. Openness is the best guarantee not just of speed and urgency in dealing with failings that endanger patients, but it is also the best way by which the lessons learned from mistakes can be spread through the system.

Our report today features two cases in which health trusts have tried to use confidentiality agreements to prevent doctors from going public about their concerns. Such gagging clauses are supposed to be outlawed by the Public Interest Disclosure Act – if they operate against the "public interest". Yet this it is a condition that many whistleblowers are understandably reluctant to test in court. That is why, after every scandal when it emerges that a whistleblower should have been taken seriously or warnings acted on earlier, ministers tend to promise new procedures that will "change the culture" in the NHS, or social services, or the criminal justice system.

Informal procedures that do not involve the courts include telephone hotlines run by independent bodies, and various independent regulators, but it is apparent that changing cultures is harder than providing another way of making an anonymous complaint.

We could go back to any of a multitude of medical malpractice cases over the past decade to illustrate how, while there have been small steps in the right direction, giant strides yet need to be taken. We could go back to the report of Jean Ritchie QC nine years ago, on the rogue gynaecologist Rodney Ledward. She attacked "a culture where consultants were seen as gods and where there were powerful inhibitions against 'telling tales'".

Compare that with the case we report today of a doctor, necessarily anonymous, who was vindicated in court five years after raising the alarm about the misconduct of a senior colleague; the doctor eventually accepted compensation tied to a gagging clause. How much has really changed?

Just as alarming as those cases where whistleblowers have been dismissed or badly treated are those where no one seems to have raised concerns and should have done, such as the Harold Shipman case or that of the Mid-Staffs hospital trust (where it later emerged that only 27 per cent of staff told internal surveys that they would be happy to be treated in their own hospital).

How, then, to achieve a fundamental change of culture in which whistleblowing should be positively welcomed?

As ever, The Independent on Sunday believes that the answer lies in greater openness still. In some cases, the suppression of whistleblowing is blamed on the pressure felt by managers to achieve NHS targets. The answer is not to abolish targets but to fit them better to patients, on the basis of more, not less, information. If targets included indicators for the quality of health outcomes, then NHS trusts would have an interest in acting swiftly upon warnings from frontline staff. Gagging clauses must go. The same principle applies across the public services: daylight is the best defence of the vulnerable.